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.
This behavior is configured with an allow
list from our full list of
bots and/or bot
categories .
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 } ) ;
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 } ) ;
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 } ) ;
return new Response ( " 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 . 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 " ;
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 . 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 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 . 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 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 . 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 { 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! " ) ;
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! " ) ;
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 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/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! " ) ;
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 search engine crawlers. See the full list of bots
// for other options: https://arcjet.com/bot-list
allow : [ " CATEGORY:SEARCH_ENGINE " ] ,
// 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 search engine crawlers. See the full list of bots
// for other options: https://arcjet.com/bot-list
allow : [ " CATEGORY:SEARCH_ENGINE " ] ,
// 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 ) ;
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 search engine crawlers. See the full list of bots
// for other options: https://arcjet.com/bot-list
allow : [ " CATEGORY:SEARCH_ENGINE " ] ,
export async function handle ({ event , resolve }) {
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , " Forbidden " ) ;
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 search engine crawlers. See the full list of bots
// for other options: https://arcjet.com/bot-list
allow : [ " CATEGORY:SEARCH_ENGINE " ] ,
export async function handle ({
resolve : ( event : RequestEvent ) => Response | Promise < Response >;
const decision = await aj . protect ( event ) ;
if ( decision . isDenied ()) {
return error ( 403 , " Forbidden " ) ;
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.
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 full result as well as the bot protection rule:
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 } ) ;
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 } ) ;
return new Response ( " Hello world " ) ;
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 " ) ;
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 " } ) ;
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 " } ) ;
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 " } )) ;
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/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! " ) ;
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/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 } ) ;
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, t