Arcjet bot detection allows you to manage traffic by automated clients and bots.
Configuration
Bot detection is configured by allowing or denying a subset of bots. The allow
and deny
lists are mutually-exclusive, such that using allow
will result in
a DENY
decision for any detected bot that is not specified in the allow
list
and using deny
will result in an ALLOW
decision for any detected bot that is
not specified in the deny
list.
You can use only one of the following configuration definitions:
mode ?: " LIVE " | " DRY_RUN " ;
allow : Array < ArcjetWellKnownBot | ArcjetBotCategory >;
mode ?: " LIVE " | " DRY_RUN " ;
deny : Array < ArcjetWellKnownBot | ArcjetBotCategory >;
The arcjet
client is configured with one or more detectBot
rules which take
one or many BotOptions
.
Allowing specific bots
Most applications want to block almost all bots. However, it is common to allow
some bots to access your system, such as bots for search indexing or API
access from the command line.
When allowing specific bots we recommend that you also check the verification
status after an allow decision is returned to ensure that the bots are who they
say they are.
This behavior is configured with an allow
list from our full list of
bots and/or bot
categories .
import { detectBot } from " @arcjet/nest " ;
// This is part of the rules constructed using withRule or a guard
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
import arcjet , { detectBot } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/node " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
import arcjet , { detectBot } from " @arcjet/node " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
import arcjet , { detectBot } from " @arcjet/deno " ;
key : Deno . env . get ( " ARCJET_KEY " ) ! , // Get your site key from https://app.arcjet.com
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/remix " ;
import type { LoaderFunctionArgs } from " @remix-run/node " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
export async function loader ( args : LoaderFunctionArgs ) {
const decision = await aj . protect ( args ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { detectBot } from " @arcjet/remix " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
export async function loader ( args ) {
const decision = await aj . protect ( args ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
export async function POST ( req : Request ) {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
if ( decision . isDenied () || decision . reason . isSpoofed ()) {
return NextResponse . json (
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
return NextResponse . json ( {
import arcjet , { detectBot } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
export default async function handler ( req , res ) {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
if ( decision . isDenied ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
} else if ( decision . reason . isSpoofed ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
export default async function handler ( req , res ) {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
if ( decision . isDenied ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
} else if ( decision . reason . isSpoofed ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
export default async function handler (
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
if ( decision . isDenied ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
} else if ( decision . reason . isSpoofed ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error } from " @sveltejs/kit " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
export async function handle ({ event , resolve }) {
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , " You are a bot! " ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return error ( 403 , " You are a bot! " ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error , type RequestEvent } from " @sveltejs/kit " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
export async function handle ({
resolve : ( event : RequestEvent ) => Response | Promise < Response >;
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , " You are a bot! " ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return error ( 403 , " You are a bot! " ) ;
Denying specific bots
Some applications may only want to block a small subset of bots, while allowing
the majority continued access. This may be due to many reasons, such as
misconfigured or high-traffic bots.
This behavior is configured with a deny
list from our full list of
bots and/or bot
categories .
import { detectBot } from " @arcjet/nest " ;
// This is part of the rules constructed using withRule or a guard
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
import arcjet , { detectBot } from " @arcjet/node " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
import arcjet , { detectBot } from " @arcjet/node " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
import arcjet , { detectBot } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/deno " ;
key : Deno . env . get ( " ARCJET_KEY " ) ! , // Get your site key from https://app.arcjet.com
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/remix " ;
import type { LoaderFunctionArgs } from " @remix-run/node " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
export async function loader ( args : LoaderFunctionArgs ) {
const decision = await aj . protect ( args ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { detectBot } from " @arcjet/remix " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
export async function loader ( args ) {
const decision = await aj . protect ( args ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
export async function POST ( req : Request ) {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied () && decision . reason . isBot ()) {
return NextResponse . json (
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
return NextResponse . json ( {
import arcjet , { detectBot } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
export default async function handler (
const decision = await aj . protect ( req ) ;
console . log ( " Decision " , decision ) ;
if ( decision . isDenied () && decision . reason . isBot ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
export async function POST ( req ) {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied () && decision . reason . isBot ()) {
return NextResponse . json (
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
return NextResponse . json ( {
import arcjet , { detectBot } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
export default async function handler (
const decision = await aj . protect ( req ) ;
console . log ( " Decision " , decision ) ;
if ( decision . isDenied () && decision . reason . isBot ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error } from " @sveltejs/kit " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
export async function handle ({ event , resolve }) {
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , " You are a bot! " ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error , type RequestEvent } from " @sveltejs/kit " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
// configured with a list of bots to deny from
// https://arcjet.com/bot-list - all other detected bots will be allowed
" CATEGORY:AI " , // denies all detected AI and LLM scrapers
" CURL " , // denies the default user-agent of the `curl` tool
export async function handle ({
resolve : ( event : RequestEvent ) => Response | Promise < Response >;
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , " You are a bot! " ) ;
Loader vs action
Remix does not support middleware, instead they
recommend calling
functions directly inside the
loader . Loaders execute before
the page is loaded.
All our examples use this pattern, but you can also execute Arcjet in an
action . This would be appropriate
to protect a form submission or other non-GET
request.
For example, you might want to run rate limiting on every GET
page load, but
use rate limiting and email validation in an action handling a form POST
.
Action
This example shows how to run Arcjet in a Remix action:
import arcjet , { detectBot } from " @arcjet/remix " ;
import type { ActionFunctionArgs } from " @remix-run/node " ;
import { redirect } from " @remix-run/node " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
export async function action ( args : ActionFunctionArgs ) {
const decision = await aj . protect ( args ) ;
if ( decision . isDenied ()) {
// This redirects to a generic error page (which you should create), but you
// could also throw an error
return redirect ( ` /error ` ) ;
// Process the action here
import arcjet , { detectBot } from " @arcjet/remix " ;
import { redirect } from " @remix-run/node " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// Google has multiple crawlers, each with a different user-agent, so we
// allow the entire Google category
" CURL " , // allows the default user-agent of the `curl` tool
" DISCORD_CRAWLER " , // allows Discordbot
export async function action ( args ) {
const decision = await aj . protect ( args ) ;
if ( decision . isDenied ()) {
// This redirects to a generic error page (which you should create), but you
// could also throw an error
return redirect ( ` /error ` ) ;
// Process the action here
Guards and routes
Arcjet can be integrated into NestJS in several places using NestJS
guards or directly within the route
controller:
Global guard: Applies Arcjet rules on every request, but does not allow
you to configure rules per route.
Per route guard: Allows you to configure rules per route, but requires you
to add the guard to every route and has limited flexibility.
Within route: Requires some code duplication, but allows maximum
flexibility because you can customize the rules and response.
Global guard
A global guard can be configured in src/app.module.ts
.
import { ArcjetModule , detectBot } from " @arcjet/nest " ;
import { Module } from " @nestjs/common " ;
import { ConfigModule } from " @nestjs/config " ;
envFilePath : " .env.local " ,
key : process . env . ARCJET_KEY ! ,
// Applies to every request
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
" CATEGORY:SEARCH_ENGINE " , // Google, Bing, etc
// Uncomment to allow these other common bot categories
// See the full list at https://arcjet.com/bot-list
//"CATEGORY:MONITOR", // Uptime monitoring services
//"CATEGORY:PREVIEW", // Link previews e.g. Slack, Discord
export class AppModule {}
This can then be added to the controller for all the routes you wish to protect
with Arcjet.
import { ArcjetGuard } from " @arcjet/nest " ;
import { Controller , Get , Injectable , UseGuards } from " @nestjs/common " ;
// This would normally go in your controller file e.g.
// src/page/page.controller.ts
// Uses the ArcjetGuard to protect the controller with the default rules defined
// in app.module.ts. Using a guard makes it easy to apply Arcjet rules, but you
// don't get access to the decision.
export class PageController {
constructor ( private readonly pageService : PageService ) {}
return this . pageService . message () ;
// This would normally go in your service file e.g.
// src/page/page.service.ts
export class PageService {
message () : { message : string } {
Per route guard
A per route guard can be configured in the controller for each route you wish to
protect with specific Arcjet rules. The client created in src/app.module.ts
is automatically passed to the guard.
The rules will be applied and a generic error returned if the result is DENY
.
import { WithArcjetRules , detectBot } from " @arcjet/nest " ;
import { Injectable , Get } from " @nestjs/common " ;
// This would normally go in your controller file e.g.
// src/page/page.controller.ts
// Attaches the ArcjetGuard to the controller to protect it with the specified
// rules extended from the global rules defined in app.module.ts.
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // blocks all automated clients
export class PageController {
constructor ( private readonly pageService : PageService ) {}
return this . pageService . message () ;
// This would normally go in your service file e.g.
// src/page/page.service.ts
export class PageService {
message () : { message : string } {
Within route
Call Arcjet from within the route controller to have maximum flexibility.
import { ARCJET , type ArcjetNest , detectBot } from " @arcjet/nest " ;
import type { Request } from " express " ;
// This would normally go in your service file e.g.
// src/page/page.service.ts
export class PageAdvancedService {
message () : { message : string } {
// This would normally go in your controller file e.g.
// src/page/page.controller.ts
// Sets up the Arcjet protection without using a guard so we can access the
// decision and use it in the controller.
export class PageAdvancedController {
private readonly pageService : PageAdvancedService ,
@ Inject ( ARCJET ) private readonly arcjet : ArcjetNest ,
async index (@ Req () req : Request ) {
const decision = await this . arcjet
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // blocks all automated clients
if ( decision . isDenied ()) {
if ( decision . reason . isBot ()) {
throw new HttpException ( " No bots allowed " , HttpStatus . FORBIDDEN ) ;
throw new HttpException ( " Forbidden " , HttpStatus . FORBIDDEN ) ;
return this . pageService . message () ;
Per route vs middleware
Bot protection rules can be configured in two ways:
Per API route : The rule is defined in the API route itself. This allows
you to configure the rule alongside the code it is protecting which is useful
if you want to use the decision to add context to your own code. However, it
means rules are not located in a single place.
Middleware : The rule is defined in the middleware. This allows you to
configure rules in a single place or apply them globally to all routes, but
it means the rules are not located alongside the code they are protecting.
Per route
This configures bot protection on a single route.
import arcjet , { detectBot } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export default async function handler ( req , res ) {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied () && decision . reason . isBot ()) {
return res . status ( 403 ) . json ( { error : " You are a bot! " } ) ;
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export default async function handler (
const decision = await aj . protect ( req ) ;
if ( decision . isDenied () && decision . reason . isBot ()) {
return res . status ( 403 ) . json ( { error : " You are a bot! " } ) ;
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export async function GET ( req : Request ) {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied () && decision . reason . isBot ()) {
return NextResponse . json (
return NextResponse . json ( {
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export async function GET ( req ) {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied () && decision . reason . isBot ()) {
return NextResponse . json (
return NextResponse . json ( {
Middleware
This will run on every request to your Next.js app, except for static assets
(configured in the matcher
- see the Next.js
docs
for details).
Create a file called middleware.ts
in your project root (at the same level as
pages
or app
or inside src
):
import arcjet , { createMiddleware , detectBot } from " @arcjet/next " ;
// matcher tells Next.js which routes to run the middleware on.
// This runs the middleware on all routes except for static assets.
matcher : [ " /((?!_next/static|_next/image|favicon.ico).*) " ] ,
key : process . env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block all bots except the following
" CATEGORY:SEARCH_ENGINE " , // Google, Bing, etc
// Uncomment to allow these other common bot categories
// See the full list at https://arcjet.com/bot-list
//"CATEGORY:MONITOR", // Uptime monitoring services
//"CATEGORY:PREVIEW", // Link previews e.g. Slack, Discord
// Pass any existing middleware with the optional existingMiddleware prop
export default createMiddleware ( aj ) ;
You can also customize the response depending on the decision. In this case we
will return a 403 Forbidden response only if we detect a hosting provider IP
address for the bot detection rule result:
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextRequest , NextResponse } from " next/server " ;
// matcher tells Next.js which routes to run the middleware on.
// This runs the middleware on all routes except for static assets.
matcher : [ " /((?!_next/static|_next/image|favicon.ico).*) " ] ,
key : process . env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
allow : [] , // "allow none" will block all detected bots
export default async function middleware ( request : NextRequest ) {
const decision = await aj . protect ( request ) ;
// If the decision is deny because the request is from a bot and the bot IP
// address is from a known hosting provider, then block the request
decision . reason . isBot () &&
return NextResponse . json ( { error : " Unauthorized " }, { status : 403 } ) ;
return NextResponse . next () ;
Create a file called middleware.js
in your project root (at the same level as
pages
or app
or inside src
):
import arcjet , { createMiddleware , detectBot } from " @arcjet/next " ;
// matcher tells Next.js which routes to run the middleware on.
// This runs the middleware on all routes except for static assets.
matcher : [ " /((?!_next/static|_next/image|favicon.ico).*) " ] ,
key : process . env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block all bots except the following
" CATEGORY:SEARCH_ENGINE " , // Google, Bing, etc
// Uncomment to allow these other common bot categories
// See the full list at https://arcjet.com/bot-list
//"CATEGORY:MONITOR", // Uptime monitoring services
//"CATEGORY:PREVIEW", // Link previews e.g. Slack, Discord
// Pass any existing middleware with the optional existingMiddleware prop
export default createMiddleware ( aj ) ;
You can also customize the response depending on the decision. In this case we
will return a 403 Forbidden response only if we detect a hosting provider IP
address for the bot detection rule result:
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
// matcher tells Next.js which routes to run the middleware on.
// This runs the middleware on all routes except for static assets.
matcher : [ " /((?!_next/static|_next/image|favicon.ico).*) " ] ,
key : process . env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
allow : [] , // "allow none" will block all detected bots
export default async function middleware ( request ) {
const decision = await aj . protect ( request ) ;
// If the decision is deny because the request is from a bot and the bot IP
// address is from a known hosting provider, then block the request
decision . reason . isBot () &&
return NextResponse . json ( { error : " Unauthorized " }, { status : 403 } ) ;
return NextResponse . next () ;
Avoiding double protection with middleware
If you use Arcjet in middleware and individual routes, you need to be careful
that Arcjet is not running multiple times per request. This can be avoided by
excluding the API route from the middleware
matcher .
For example, if you already have a bot detection rule defined in the API route
at /api/hello
, you can exclude it from the middleware by specifying a matcher
in /middleware.ts
:
import arcjet , { createMiddleware , detectBot } from " @arcjet/next " ;
// The matcher prevents the middleware executing on static assets and the
// /api/hello API route because you already installed Arcjet directly
matcher : [ " /((?!_next/static|_next/image|favicon.ico|api/hello).*) " ] ,
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
// Pass any existing middleware with the optional existingMiddleware prop
export default createMiddleware ( aj ) ;
Pages & Server Actions
Arcjet can be used inside Next.js middleware, API routes, pages, server
components, and server actions. Client components cannot be protected because
they run on the client only.
See the Next.js SDK reference for examples of pages / page
components and server
actions .
Per route vs hooks
Bot protection rules can be configured in two ways:
Per route : The rule is defined in the route handler itself. This allows
you to configure the rule alongside the code it is protecting which is useful
if you want to use the decision to add context to your own code. However, it
means rules are not located in a single place.
Hooks : The rule is defined as a hook. This allows you to
configure rules in a single place or apply them globally to all routes, but
it means the rules are not located alongside the code they are protecting.
Per route
This configures bot protection on a single route.
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error , json , type RequestEvent } from " @sveltejs/kit " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
export async function GET ( event : RequestEvent ) {
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , { message : " Forbidden " } ) ;
return json ( { message : " Hello world " } ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error , json } from " @sveltejs/kit " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
export async function GET ( event ) {
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , { message : " Forbidden " } ) ;
return json ( { message : " Hello world " } ) ;
Hooks
This will run on every request to your SvelteKit app - see the SvelteKit Hooks
docs for details.
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error } from " @sveltejs/kit " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block all bots except the following
" CATEGORY:SEARCH_ENGINE " , // Google, Bing, etc
// Uncomment to allow these other common bot categories
// See the full list at https://arcjet.com/bot-list
//"CATEGORY:MONITOR", // Uptime monitoring services
//"CATEGORY:PREVIEW", // Link previews e.g. Slack, Discord
export async function handle ({ event , resolve }) {
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , " Forbidden " ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return error ( 403 , " You are a bot! " ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error , type RequestEvent } from " @sveltejs/kit " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block all bots except the following
" CATEGORY:SEARCH_ENGINE " , // Google, Bing, etc
// Uncomment to allow these other common bot categories
// See the full list at https://arcjet.com/bot-list
//"CATEGORY:MONITOR", // Uptime monitoring services
//"CATEGORY:PREVIEW", // Link previews e.g. Slack, Discord
export async function handle ({
resolve : ( event : RequestEvent ) => Response | Promise < Response >;
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , " Forbidden " ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return error ( 403 , " You are a bot! " ) ;
Avoiding double protection with hooks
If you use Arcjet in hooks and individual routes, you need to be careful
that Arcjet is not running multiple times per request. This can be avoided by
excluding the individual routes before running Arcjet in the hook.
For example, if you already have rules defined in the API route
at /api/arcjet
, you can exclude it from the hook like this:
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error , type RequestEvent } from " @sveltejs/kit " ;
allow : [] , // "allow none" will block all detected bots
export async function handle ({
resolve : ( event : RequestEvent ) => Response | Promise < Response >;
// Ignore routes that extend the Arcjet rules
// - they will call `.protect` themselves
const filteredRoutes = [ " /api/arcjet " ] ;
if ( filteredRoutes . includes ( event . url . pathname )) {
// return - route will handle protecttion
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , " Forbidden " ) ;
Decision
The quick start example will deny requests that
match the bot detection rules, immediately returning a response to the client.
Arcjet also provides a single protect
function that is used to execute your
protection rules. This requires a request
argument which is the request
context as passed to the request handler.
If you are using a global guard or per route
guard then protect
is called for you behind the scenes. If you add Arcjet
within a route then you call it directly.
This function returns a Promise
that resolves to an
ArcjetDecision
object. This contains the following properties:
id
(string
) - The unique ID for the request. This can be used to look up
the request in the Arcjet dashboard. It is prefixed with req_
for decisions
involving the Arcjet cloud API. For decisions taken locally, the prefix is
lreq_
.
conclusion
(ArcjetConclusion
) - The final conclusion based on evaluating
each of the configured rules. If you wish to accept Arcjet’s recommended
action based on the configured rules then you can use this property.
reason
(ArcjetReason
) - An object containing more detailed
information about the conclusion.
results
(ArcjetRuleResult[]
) - An array of ArcjetRuleResult
objects
containing the results of each rule that was executed.
ip
(ArcjetIpDetails
) - An object containing Arcjet’s analysis of the
client IP address. See the SDK reference for more information.
You check if a deny conclusion has been returned by a bot protection rule by
using decision.isDenied()
and decision.reason.isBot()
respectively.
You can iterate through the results and check whether a bot protection rule was
applied:
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
This example will log the results of each rule execution.
import arcjet , { detectBot , fixedWindow } from " @arcjet/deno " ;
key : Deno . env . get ( " ARCJET_KEY " ) ! , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
console . log ( " Arcjet decision " , decision ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
This example will log the results of each rule execution.
import arcjet , { detectBot , fixedWindow } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
console . log ( " Arcjet decision " , decision ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot , fixedWindow } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
console . log ( " Arcjet decision " , decision ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
This example will log the results of each rule execution.
import arcjet , { detectBot , fixedWindow } from " @arcjet/remix " ;
import type { LoaderFunctionArgs } from " @remix-run/node " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export async function loader ( args : LoaderFunctionArgs ) {
const decision = await aj . protect ( args ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { detectBot , fixedWindow } from " @arcjet/remix " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export async function loader ( args ) {
const decision = await aj . protect ( args ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
This example will log the results of each rule execution.
import arcjet , { fixedWindow , detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
// Limiting by ip.src is the default if not specified
//characteristics: ["ip.src"],
allow : [] , // "allow none" will block all detected bots
export async function POST ( req : Request ) {
const decision = await aj . protect ( req ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
return NextResponse . json ( { error : " Forbidden " }, { status : 403 } ) ;
return NextResponse . json ( {
import arcjet , { fixedWindow , detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
// Limiting by ip.src is the default if not specified
//characteristics: ["ip.src"],
allow : [] , // "allow none" will block all detected bots
export async function POST ( req ) {
const decision = await aj . protect ( req ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
return NextResponse . json ( { error : " Forbidden " }, { status : 403 } ) ;
return NextResponse . json ( {
import arcjet , { fixedWindow , detectBot } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
// Limiting by ip.src is the default if not specified
//characteristics: ["ip.src"],
allow : [] , // "allow none" will block all detected bots
export default async function handler ( req , res ) {
const decision = await aj . protect ( req ) ;
console . log ( " Decision " , decision ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
. json ( { error : " Forbidden " , reason : decision . reason } ) ;
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { fixedWindow , detectBot } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
// Limiting by ip.src is the default if not specified
//characteristics: ["ip.src"],
allow : [] , // "allow none" will block all detected bots
export default async function handler (
const decision = await aj . protect ( req ) ;
console . log ( " Decision " , decision ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
. json ( { error : " Forbidden " , reason : decision . reason } ) ;
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
This example will log the results of each rule execution.
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot , fixedWindow } from " @arcjet/sveltekit " ;
import { error , json , type RequestEvent } from " @sveltejs/kit " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
export async function POST ( event : RequestEvent ) {
const decision = await aj . protect ( event ) ;
console . log ( " Arcjet decision " , decision ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
return error ( 403 , " Forbidden " ) ;
return json ( { message : " Hello world " } ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot , fixedWindow } from " @arcjet/sveltekit " ;
import { error , json } from " @sveltejs/kit " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
export async function POST ( event ) {
const decision = await aj . protect ( event ) ;
console . log ( " Arcjet decision " , decision ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
return error ( 403 , " Forbidden " ) ;
return json ( { message : " Hello world " } ) ;
This example will log the results of each rule execution.
import arcjet , { fixedWindow , detectBot } from " @arcjet/node " ;
import http from " node:http " ;
key : process . env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
characteristics : [ " ip.src " ] ,
allow : [] , // "allow none" will block all detected bots
const server = http . createServer ( async function ( req , res ) {
const decision = await aj . protect ( req ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isRateLimit ()) {
res . writeHead ( 429 , { " Content-Type " : " application/json " } ) ;
JSON . stringify ( { error : " Too Many Requests " , reason : decision . reason } ) ,
res . end ( JSON . stringify ( { error : " Forbidden " } )) ;
res . writeHead ( 403 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { error : " Forbidden " } )) ;
res . writeHead ( 200 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { message : " Hello world " } )) ;
import arcjet , { fixedWindow , detectBot } from " @arcjet/node " ;
import http from " node:http " ;
key : process . env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
characteristics : [ " ip.src " ] ,
allow : [] , // "allow none" will block all detected bots
const server = http . createServer ( async function (
req : http . IncomingMessage ,
res : http . ServerResponse ,
const decision = await aj . protect ( req ) ;
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
console . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
console . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isRateLimit ()) {
res . writeHead ( 429 , { " Content-Type " : " application/json " } ) ;
JSON . stringify ( { error : " Too Many Requests " , reason : decision . reason } ) ,
res . end ( JSON . stringify ( { error : " Forbidden " } )) ;
res . writeHead ( 403 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { error : " Forbidden " } )) ;
res . writeHead ( 200 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { message : " Hello world " } )) ;
This example will log the results of each rule execution. It shows how Arcjet
can be integrated into the NestJS logger. See the SDK
reference for more details.
import { ARCJET , type ArcjetNest , detectBot , fixedWindow } from " @arcjet/nest " ;
import type { Request } from " express " ;
// This would normally go in your service file e.g.
// src/page/page.service.ts
export class PageService {
message () : { message : string } {
// This would normally go in your controller file e.g.
// src/page/page.controller.ts
// Sets up the Arcjet protection without using a guard so we can access the
// decision and use it in the controller.
export class PageController {
// Make use of the NestJS logger: https://docs.nestjs.com/techniques/logger
// https://github.com/arcjet/example-nestjs/blob/ec742e58c8da52d0a399327182c79e3f4edc8f3b/src/app.module.ts#L29
// and https://github.com/arcjet/example-nestjs/blob/main/src/arcjet-logger.ts
// for an example of how to connect Arcjet to the NestJS logger
private readonly logger = new Logger ( PageController . name ) ;
private readonly pageService : PageService ,
@ Inject ( ARCJET ) private readonly arcjet : ArcjetNest ,
async index (@ Req () req : Request ) {
const decision = await this . arcjet
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // blocks all automated clients
this . logger . log ( ` Arcjet: id = ${ decision . id }` ) ;
this . logger . log ( ` Arcjet: decision = ${ decision . conclusion }` ) ;
for ( const result of decision . results ) {
this . logger . log ( " Rule Result " , result ) ;
if ( result . reason . isRateLimit ()) {
this . logger . log ( " Rate limit rule " , result ) ;
if ( result . reason . isBot ()) {
this . logger . log ( " Bot protection rule " , result ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isBot ()) {
throw new HttpException ( " No bots allowed " , HttpStatus . FORBIDDEN ) ;
throw new HttpException ( " Forbidden " , HttpStatus . FORBIDDEN ) ;
return this . pageService . message () ;
Identified bots
The decision also contains all of the identified
bots and matched categories detected from the
request. A request may be identified as zero, one, or more bots/categories—all
of which will be available on the decision.allowed
and decision.denied
properties.
import arcjet , { detectBot } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
allow : [] , // "allow none" will block all detected bots
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
allow : [] , // "allow none" will block all detected bots
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/deno " ;
key : Deno . env . get ( " ARCJET_KEY " ) ! , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
allow : [] , // "allow none" will block all detected bots
aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export async function POST ( req : Request ) {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
return NextResponse . json ( { error : " You are a bot! " }, { status : 403 } ) ;
return NextResponse . json ( {
import arcjet , { detectBot } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export default async function handler ( req , res ) {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
return res . status ( 403 ) . json ( { error : " Forbidden " } ) ;
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export default async function handler (
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
return res . status ( 403 ) . json ( { error : " Forbidden " } ) ;
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export async function POST ( req ) {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
return NextResponse . json ( { error : " You are a bot! " }, { status : 403 } ) ;
return NextResponse . json ( {
import arcjet , { detectBot } from " @arcjet/remix " ;
import type { LoaderFunctionArgs } from " @remix-run/node " ;
key : process . env . ARCJET_KEY ! ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
allow : [] , // "allow none" will block all detected bots
export async function loader ( args : LoaderFunctionArgs ) {
const decision = await aj . protect ( args ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { detectBot } from " @arcjet/remix " ;
key : process . env . ARCJET_KEY ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
allow : [] , // "allow none" will block all detected bots
export async function loader ( args ) {
const decision = await aj . protect ( args ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { detectBot } from " @arcjet/node " ;
import http from " node:http " ;
key : process . env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
allow : [] , // "allow none" will block all detected bots
const server = http . createServer ( async function ( req , res ) {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
res . writeHead ( 403 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { error : " Forbidden " } )) ;
res . writeHead ( 200 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { message : " Hello world " } )) ;
import arcjet , { detectBot } from " @arcjet/node " ;
import http from " node:http " ;
key : process . env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
allow : [] , // "allow none" will block all detected bots
const server = http . createServer ( async function (
req : http . IncomingMessage ,
res : http . ServerResponse ,
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
res . writeHead ( 403 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { error : " Forbidden " } )) ;
res . writeHead ( 200 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { message : " Hello world " } )) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error } from " @sveltejs/kit " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
export async function handle ({ event , resolve }) {
const decision = await aj . protect ( event ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
return error ( 403 , " You are a bot! " ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error , type RequestEvent } from " @sveltejs/kit " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
export async function handle ({
resolve : ( event : RequestEvent ) => Response | Promise < Response >;
const decision = await aj . protect ( event ) ;
if ( decision . reason . isBot ()) {
console . log ( " detected + allowed bots " , decision . reason . allowed ) ;
console . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
return error ( 403 , " You are a bot! " ) ;
import { ARCJET , type ArcjetNest , detectBot } from " @arcjet/nest " ;
import type { Request } from " express " ;
// This would normally go in your service file e.g.
// src/page/page.service.ts
export class PageService {
message () : { message : string } {
// This would normally go in your controller file e.g.
// src/page/page.controller.ts
// Sets up the Arcjet protection without using a guard so we can access the
// decision and use it in the controller.
export class PageController {
// Make use of the NestJS logger: https://docs.nestjs.com/techniques/logger
// https://github.com/arcjet/example-nestjs/blob/ec742e58c8da52d0a399327182c79e3f4edc8f3b/src/app.module.ts#L29
// and https://github.com/arcjet/example-nestjs/blob/main/src/arcjet-logger.ts
// for an example of how to connect Arcjet to the NestJS logger
private readonly logger = new Logger ( PageController . name ) ;
private readonly pageService : PageService ,
@ Inject ( ARCJET ) private readonly arcjet : ArcjetNest ,
async index (@ Req () req : Request ) {
const decision = await this . arcjet
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // blocks all automated clients
if ( decision . reason . isBot ()) {
this . logger . log ( " detected + allowed bots " , decision . reason . allowed ) ;
this . logger . log ( " detected + denied bots " , decision . reason . denied ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isBot ()) {
throw new HttpException ( " No bots allowed " , HttpStatus . FORBIDDEN ) ;
throw new HttpException ( " Forbidden " , HttpStatus . FORBIDDEN ) ;
return this . pageService . message () ;
Error handling
Arcjet is designed to fail open so that a service issue or misconfiguration does
not block all requests. The SDK will also time out and fail open after 1000ms
when NODE_ENV
or ARCJET_ENV
is development
and 500ms otherwise. However,
in most cases, the response time will be less than 20-30ms.
If there is an error condition, Arcjet will return an
ERROR
type and you can check the reason
property for more information, like
accessing decision.reason.message
.
Note
Requests without User-Agent
headers can not be identified as any particular
bot and will be marked as an errored decision. Check decision.isErrored()
and
decide if you want to allow or deny the request. Our recommendation is to block
requests without User-Agent
headers because most legitimate clients always
send this header.
See an example of how to do this .
import arcjet , { detectBot } from " @arcjet/deno " ;
key : Deno . env . get ( " ARCJET_KEY " ) ! , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//return new Response("Service unavailable", { status: 503 });
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//return new Response("Service unavailable", { status: 503 });
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
allow : [] , // "allow none" will block all detected bots
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//return new Response("Service unavailable", { status: 503 });
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { detectBot } from " @arcjet/remix " ;
import type { LoaderFunctionArgs } from " @remix-run/node " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export async function loader ( args : LoaderFunctionArgs ) {
const decision = await aj . protect ( args ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//throw new Response("Service unavailable", { status: 503 });
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { detectBot } from " @arcjet/remix " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export async function loader ( args ) {
const decision = await aj . protect ( args ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//throw new Response("Service unavailable", { status: 503 });
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export default async function handler ( req , res ) {
const decision = await aj . protect ( req ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//return res.status(503).json({ error: "Service unavailable" });
if ( decision . isDenied ()) {
return res . status ( 403 ) . json ( {
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export default async function handler (
const decision = await aj . protect ( req ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//return res.status(503).json({ error: "Service unavailable" });
if ( decision . isDenied ()) {
return res . status ( 403 ) . json ( {
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export async function GET ( req : Request ) {
const decision = await aj . protect ( req ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//return NextResponse.json({ error: "Service unavailable" }, { status: 503 });
if ( decision . isDenied ()) {
return NextResponse . json (
return NextResponse . json ( {
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export async function GET ( req ) {
const decision = await aj . protect ( req ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//return NextResponse.json({ error: "Service unavailable" }, { status: 503 });
if ( decision . isDenied ()) {
return NextResponse . json (
return NextResponse . json ( {
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error , json , type RequestEvent } from " @sveltejs/kit " ;
allow : [] , // "allow none" will block all detected bots
export async function GET ( event : RequestEvent ) {
const decision = await aj . protect ( event ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//return error(503, { message: "Service unavailable" });
if ( decision . isDenied ()) {
return error ( 403 , { message : " You are a bot! " } ) ;
return json ( { message : " Hello world " } ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { detectBot } from " @arcjet/sveltekit " ;
import { error , json } from " @sveltejs/kit " ;
allow : [] , // "allow none" will block all detected bots
export async function GET ( event ) {
const decision = await aj . protect ( event ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//return error(503, { message: "Service unavailable" });
if ( decision . isDenied ()) {
return error ( 403 , { message : " You are a bot! " } ) ;
return json ( { message : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/node " ;
import http from " node:http " ;
key : process . env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
allow : [] , // "allow none" will block all detected bots
const server = http . createServer ( async function ( req , res ) {
const decision = await aj . protect ( req ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//res.writeHead(503, { "Content-Type": "application/json" });
//res.end(JSON.stringify({ error: "Service unavailable" }));
if ( decision . isDenied ()) {
res . writeHead ( 403 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { error : " Forbidden " } )) ;
res . writeHead ( 200 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { message : " Hello world " } )) ;
import arcjet , { detectBot } from " @arcjet/node " ;
import http from " node:http " ;
key : process . env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
allow : [] , // "allow none" will block all detected bots
const server = http . createServer ( async function (
req : http . IncomingMessage ,
res : http . ServerResponse ,
const decision = await aj . protect ( req ) ;
// If the request is missing a User-Agent header, the decision will be
// marked as an error! You should check for this and make a decision about
// the request since requests without a User-Agent could indicate a crafted
// request from an automated client.
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here if the request is missing a User-Agent
//res.writeHead(503, { "Content-Type": "application/json" });
//res.end(JSON.stringify({ error: "Service unavailable" }));
if ( decision . isDenied ()) {
res . writeHead ( 403 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { error : " Forbidden " } )) ;
res . writeHead ( 200 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { message : " Hello world " } )) ;
import { ARCJET , type ArcjetNest , detectBot } from " @arcjet/nest " ;
import type { Request } from " express " ;
// This would normally go in your service file e.g.
// src/page/page.service.ts
export class PageService {
message () : { message : string } {
// This would normally go in your controller file e.g.
// src/page/page.controller.ts
// Sets up the Arcjet protection without using a guard so we can access the
// decision and use it in the controller.
export class PageController {
// Make use of the NestJS logger: https://docs.nestjs.com/techniques/logger
// https://github.com/arcjet/example-nestjs/blob/ec742e58c8da52d0a399327182c79e3f4edc8f3b/src/app.module.ts#L29
// and https://github.com/arcjet/example-nestjs/blob/main/src/arcjet-logger.ts
// for an example of how to connect Arcjet to the NestJS logger
private readonly logger = new Logger ( PageController . name ) ;
private readonly pageService : PageService ,
@ Inject ( ARCJET ) private readonly arcjet : ArcjetNest ,
async index (@ Req () req : Request ) {
const decision = await this . arcjet
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // blocks all automated clients
if ( decision . isDenied ()) {
if ( decision . reason . isBot ()) {
throw new HttpException ( " No bots allowed " , HttpStatus . FORBIDDEN ) ;
throw new HttpException ( " Forbidden " , HttpStatus . FORBIDDEN ) ;
} else if ( decision . isErrored ()) {
if ( decision . reason . message . includes ( " missing User-Agent header " )) {
// Requests without User-Agent headers can not be identified as any
// particular bot and will be marked as an errored decision. Most
// legitimate clients always send this header, so we recommend blocking
this . logger . warn ( " User-Agent header is missing " ) ;
throw new HttpException ( " Bad request " , HttpStatus . BAD_REQUEST ) ;
// Fail open to prevent an Arcjet error from blocking all requests. You
// may want to fail closed if this controller is very sensitive
this . logger . error ( ` Arcjet error: ${ decision . reason . message }` ) ;
return this . pageService . message () ;
Filtering categories
All categories are also provided as enumerations, which allows for programmatic
access. For example, you may want to allow most of CATEGORY:GOOGLE
except
their “advertising quality” bot.
import { botCategories , detectBot } from " @arcjet/nest " ;
// This is part of the rules constructed using withRule or a guard
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
import arcjet , { botCategories , detectBot } from " @arcjet/node " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
import arcjet , { botCategories , detectBot } from " @arcjet/node " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
import arcjet , { botCategories , detectBot } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { botCategories , detectBot } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
fetch : aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { botCategories , detectBot } from " @arcjet/deno " ;
key : Deno . env . get ( " ARCJET_KEY " ) ! , // Get your site key from https://app.arcjet.com
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
aj . handler ( async ( req ) => {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { botCategories , detectBot } from " @arcjet/remix " ;
import type { LoaderFunctionArgs } from " @remix-run/node " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
export async function loader ( args : LoaderFunctionArgs ) {
const decision = await aj . protect ( args ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { botCategories , detectBot } from " @arcjet/remix " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
export async function loader ( args ) {
const decision = await aj . protect ( args ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { botCategories , detectBot } from " @arcjet/sveltekit " ;
import { error } from " @sveltejs/kit " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
export async function handle ({ event , resolve }) {
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , " You are a bot! " ) ;
if ( decision . reason . isBot () && decision . reason . isSpoofed ()) {
return error ( 403 , " You are a bot! " ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { botCategories , detectBot } from " @arcjet/sveltekit " ;
import { error , type RequestEvent } from " @sveltejs/kit " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
export async function handle ({
resolve : ( event : RequestEvent ) => Response | Promise < Response >;
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , " You are a bot! " ) ;
import arcjet , { botCategories , detectBot } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
export default async function handler ( req , res ) {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
if ( decision . isDenied ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
} else if ( decision . reason . isSpoofed ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { botCategories , detectBot } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
export default async function handler (
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
if ( decision . isDenied ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
} else if ( decision . reason . isSpoofed ()) {
return res . status ( 403 ) . json ( {
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { botCategories , detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
export async function POST ( req : Request ) {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
if ( decision . isDenied ()) {
return NextResponse . json (
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
} else if ( decision . reason . isSpoofed ()) {
return NextResponse . json (
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
return NextResponse . json ( {
import arcjet , { botCategories , detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list - all other detected bots will be blocked
// filter a category to remove individual bots from our provided lists
... botCategories [ " CATEGORY:GOOGLE " ] . filter (
( bot ) => bot !== " GOOGLE_ADSBOT " && bot !== " GOOGLE_ADSBOT_MOBILE " ,
export async function POST ( req ) {
const decision = await aj . protect ( req ) ;
if ( decision . reason . isBot ()) {
if ( decision . isDenied ()) {
return NextResponse . json (
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
} else if ( decision . reason . isSpoofed ()) {
return NextResponse . json (
// Useful for debugging, but don't return these to the client in
denied : decision . reason . denied ,
return NextResponse . json ( {
Bot verification
We support verifying the authenticity of requests from some bots by
comparing the request IP to published bot IP ranges or performing a reverse
DNS query. Verification is performed for supported bots using the appropriate method
automatically after the bot is identified by Arcjet.
To check the verification status,
use the .isSpoofed()
or .isVerified()
methods on the bot reason object. If
verification was performed, one of these will be true and the other false; both
will be false if verification failed or if we don’t support verifying the identified bot.
Here’s a basic usage example:
if ( decision . reason . isSpoofed ()) {
// Show a custom block page for spoofed bots
} else if ( decision . reason . isVerified ()) {
// You can now trust that the bot is who they say they are and proceed as normal
// The bot either does not support verification, or verification failed.
Testing
Arcjet runs the same in any environment, including locally and in CI. You can
use the mode
set to DRY_RUN
to log the results of rule execution without
blocking any requests.
We have an example test framework you can use to automatically test your rules.
Arcjet can also be triggered based using a sample of your traffic.
See the Testing section of the docs for details.
Examples
Protecting a page
You can protect a Next.js page from bots by calling the Arcjet SDK from within
the page loader:
Protecting an app router page within the handler itself is not currently
supported, but you can set up a matcher on the middleware instead:
import arcjet , { createMiddleware , detectBot } from " @arcjet/next " ;
// The matcher runs just on the /hello pages route
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
// Pass any existing middleware with the optional existingMiddleware prop
export default createMiddleware ( aj ) ;
Protecting an app router page within the handler itself is not currently
supported, but you can set up a matcher on the middleware instead:
import arcjet , { createMiddleware , detectBot } from " @arcjet/next " ;
// The matcher runs just on the /hello pages route
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
// Pass any existing middleware with the optional existingMiddleware prop
export default createMiddleware ( aj ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import Error from " next/error " ;
import Head from " next/head " ;
import React from " react " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
// getServerSideProps is called on the server before rendering the page
export const getServerSideProps = async ( context ) => {
const decision = await aj . protect ( context . req ) ;
console . log ( " decision " , decision ) ;
if ( decision . isDenied ()) {
props : { pageProps : { errorCode : 403 , errorText : " Access denied " } },
return { props : { pageProps : { errorCode : false , errorText : "" } } };
export default function Page ({ pageProps }) {
// If there is an error, render the Next.js error page
if ( pageProps . errorCode ) {
< Error statusCode = { pageProps . errorCode } title = { pageProps . errorText } />
< meta name = " viewport " content = " width=device-width, initial-scale=1 " />
import arcjet , { detectBot } from " @arcjet/next " ;
import type { GetServerSideProps , InferGetServerSidePropsType } from " next " ;
import Error from " next/error " ;
import Head from " next/head " ;
import React from " react " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
errorCode : number | false ;
// getServerSideProps is called on the server before rendering the page
export const getServerSideProps = ( async ( context ) => {
const decision = await aj . protect ( context . req ) ;
console . log ( " decision " , decision ) ;
if ( decision . isDenied ()) {
props : { pageProps : { errorCode : 403 , errorText : " Access denied " } },
return { props : { pageProps : { errorCode : false , errorText : "" } } };
} ) satisfies GetServerSideProps <{
export default function Page ({
} : InferGetServerSidePropsType < typeof getServerSideProps >) {
// If there is an error, render the Next.js error page
if ( pageProps . errorCode ) {
< Error statusCode = { pageProps. errorCode } title = { pageProps. errorText } />
< meta name = " viewport " content = " width=device-width, initial-scale=1 " />
Wrap existing handler
All the examples on this page show how you can inspect the decision to control
what to do next. However, if you just wish to send a generic 403 Forbidden
response you can delegate this to Arcjet by wrapping your handler withArcjet
.
For both the Node or Edge runtime :
import arcjet , { detectBot , withArcjet } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export const GET = withArcjet ( aj , async ( req : Request ) => {
return NextResponse . json ( {
For both the Node or Edge runtime :
import arcjet , { detectBot , withArcjet } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export const GET = withArcjet ( aj , async ( req ) => {
return NextResponse . json ( {
For the Node (default) runtime:
import arcjet , { detectBot , withArcjet } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export default withArcjet (
async ( req : NextApiRequest , res : NextApiResponse ) => {
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
For the Edge runtime:
import arcjet , { detectBot , withArcjet } from " @arcjet/next " ;
import { NextRequest , NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export default withArcjet ( aj , async ( req : NextRequest ) => {
return NextResponse . json ( {
For the Node (default) runtime:
import arcjet , { detectBot , withArcjet } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export default withArcjet ( aj , async ( req , res ) => {
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
For the Edge runtime:
import arcjet , { detectBot , withArcjet } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export default withArcjet ( aj , async ( req ) => {
return NextResponse . json ( {
Edge Functions
Arcjet works in Edge Functions and with the Edge
Runtime .
import arcjet , { detectBot } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export default async function handler ( req , res ) {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return res . status ( 403 ) . json ( { error : " You are a bot! " } ) ;
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export default async function handler (
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return res . status ( 403 ) . json ( { error : " You are a bot! " } ) ;
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextRequest , NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
allow : [] , // "allow none" will block all detected bots
export default async function handler ( req : NextRequest , res : NextResponse ) {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return NextResponse . json (
return NextResponse . json ( {
import arcjet , { detectBot } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
allow : [] , // "allow none" will block all detected bots
export async function GET ( req ) {
const decision = await aj . protect ( req ) ;
if ( decision . isDenied ()) {
return NextResponse . json (
return NextResponse . json ( {
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