Arcjet rate limiting allows you to define rules which limit the number of
requests a client can make over a period of time.
Configuration
Each rate limit is configured on an exact path with a set of client
characteristics and algorithm specific options.
Fixed window rate limit options
Tracks the number of requests made by a client over a fixed time window. Options
are explained in the Configuration
documentation. See the fixed window algorithm
description for more details about how
the algorithm works.
// Options for fixed window rate limit
// See https://docs.arcjet.com/rate-limiting/configuration
type FixedWindowRateLimitOptions = {
// "LIVE" will block requests. "DRY_RUN" will log only
mode ?: " LIVE " | " DRY_RUN " ;
// How the client is identified. We recommend setting characteristics on the
// Arcjet client rather than per rule. Global characteristics default to the
characteristics ?: string [] ;
// Time window the rate limit applies to
// Maximum number of requests allowed in the time window
Fixed window example
import { fixedWindow } from " @arcjet/nest " ;
// This is part of the rules constructed using withRule or a guard
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
window : " 60s " , // 60 second fixed window
max : 100 , // allow a maximum of 100 requests
import arcjet , { fixedWindow } 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
window : " 60s " , // 60 second fixed window
max : 100 , // allow a maximum of 100 requests
import arcjet , { fixedWindow } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
window : " 60s " , // 60 second fixed window
max : 100 , // allow a maximum of 100 requests
import arcjet , { fixedWindow } from " @arcjet/node " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
window : " 60s " , // 60 second fixed window
max : 100 , // allow a maximum of 100 requests
import arcjet , { fixedWindow } from " @arcjet/remix " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
window : " 60s " , // 60 second fixed window
max : 100 , // allow a maximum of 100 requests
import arcjet , { fixedWindow } from " @arcjet/sveltekit " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
window : " 60s " , // 60 second fixed window
max : 100 , // allow a maximum of 100 requests
Sliding window rate limit options
Tracks the number of requests made by a client over a sliding window so that the
window moves with time. Options are explained in the
Configuration documentation. See the sliding
window algorithm description for more
details about how the algorithm works.
// Options for sliding window rate limit
// See https://docs.arcjet.com/rate-limiting/configuration
type SlidingWindowRateLimitOptions = {
// "LIVE" will block requests. "DRY_RUN" will log only
mode ?: " LIVE " | " DRY_RUN " ;
// How the client is identified. We recommend setting characteristics on the
// Arcjet client rather than per rule. Global characteristics default to the
characteristics ?: string [] ;
// The time interval in seconds for the rate limit
// Maximum number of requests allowed over the time interval
Sliding window example
import { slidingWindow } from " @arcjet/nest " ;
// This is part of the rules constructed using withRule or a guard
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
interval : 60 , // 60 second sliding window
max : 100 , // allow a maximum of 100 requests
import arcjet , { slidingWindow } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
interval : 60 , // 60 second sliding window
max : 100 , // allow a maximum of 100 requests
import arcjet , { slidingWindow } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
interval : 60 , // 60 second sliding window
max : 100 , // allow a maximum of 100 requests
import arcjet , { slidingWindow } from " @arcjet/node " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
interval : 60 , // 60 second sliding window
max : 100 , // allow a maximum of 100 requests
import arcjet , { slidingWindow } from " @arcjet/remix " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
interval : 60 , // 60 second sliding window
max : 100 , // allow a maximum of 100 requests
import arcjet , { slidingWindow } from " @arcjet/sveltekit " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
interval : 60 , // 60 second sliding window
max : 100 , // allow a maximum of 100 requests
Token bucket rate limit options
Based on a bucket filled with a specific number of tokens. Each request
withdraws a token from the bucket and the bucket is refilled at a fixed rate.
Once the bucket is empty, the client is blocked until the bucket refills.
Options are explained in the Configuration
documentation. See the token bucket algorithm
description for more details about how
the algorithm works.
// Options for token bucket rate limit
// See https://docs.arcjet.com/rate-limiting/configuration
type TokenBucketRateLimitOptions = {
// "LIVE" will block requests. "DRY_RUN" will log only
mode ?: " LIVE " | " DRY_RUN " ;
// How the client is identified. We recommend setting characteristics on the
// Arcjet client rather than per rule. Global characteristics default to the
characteristics ?: string [] ;
// Number of tokens to add to the bucket at each interval
// The interval in seconds to add tokens to the bucket
// The maximum number of tokens the bucket can hold
Token bucket example
See the token bucket request example for how to specify
the number of tokens to request.
import { tokenBucket } from " @arcjet/nest " ;
// This is part of the rules constructed using withRule or a guard
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
refillRate : 10 , // refill 10 tokens per interval
interval : 60 , // 60 second interval
capacity : 100 , // bucket maximum capacity of 100 tokens
import arcjet , { tokenBucket } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
refillRate : 10 , // refill 10 tokens per interval
interval : 60 , // 60 second interval
capacity : 100 , // bucket maximum capacity of 100 tokens
import arcjet , { tokenBucket } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
refillRate : 10 , // refill 10 tokens per interval
interval : 60 , // 60 second interval
capacity : 100 , // bucket maximum capacity of 100 tokens
import arcjet , { tokenBucket } from " @arcjet/node " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
refillRate : 10 , // refill 10 tokens per interval
interval : 60 , // 60 second interval
capacity : 100 , // bucket maximum capacity of 100 tokens
import arcjet , { tokenBucket } from " @arcjet/remix " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
refillRate : 10 , // refill 10 tokens per interval
interval : 60 , // 60 second interval
capacity : 100 , // bucket maximum capacity of 100 tokens
import arcjet , { tokenBucket } from " @arcjet/sveltekit " ;
key : process . env . ARCJET_KEY ! ,
characteristics : [ " ip.src " ] , // track requests by IP address
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
refillRate : 10 , // refill 10 tokens per interval
interval : 60 , // 60 second interval
capacity : 100 , // bucket maximum capacity of 100 tokens
Identifying users
Rate limit rules use characteristics
to identify the client and apply the
limit across requests. The default is to use the client’s IP address. However,
you can specify other
characteristics such as a user
ID or other metadata from your application.
In this example we define a rate limit rule that applies to a specific user ID.
The custom characteristic is userId
with the value passed as a prop on the
protect
function. You can use any string for the characteristic name and any
string
, number
or boolean
for the value.
import arcjet , { fixedWindow } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
// Define a custom userId characteristic.
// See https://docs.arcjet.com/rate-limiting/configuration#characteristics
characteristics : [ " userId " ] ,
fetch : aj . handler ( async ( req ) => {
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( req , { userId : " user123 " } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isDenied ()) {
return new Response ( " Too many requests " , { status : 429 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { fixedWindow } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
// Define a custom userId characteristic.
// See https://docs.arcjet.com/rate-limiting/configuration#characteristics
characteristics : [ " userId " ] ,
fetch : aj . handler ( async ( req ) => {
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( req , { userId : " user123 " } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isDenied ()) {
return new Response ( " Too many requests " , { status : 429 } ) ;
return new Response ( " Hello world " ) ;
import arcjet , { fixedWindow } from " @arcjet/remix " ;
import type { LoaderFunctionArgs } from " @remix-run/node " ;
key : process . env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
// Define a custom userId characteristic.
// See https://docs.arcjet.com/rate-limiting/configuration#characteristics
characteristics : [ " userId " ] ,
export async function loader ( args : LoaderFunctionArgs ) {
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( args , { userId : " user123 " } ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { fixedWindow } from " @arcjet/remix " ;
key : process . env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
// Define a custom userId characteristic.
// See https://docs.arcjet.com/rate-limiting/configuration#characteristics
characteristics : [ " userId " ] ,
export async function loader ( args ) {
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( args , { userId : " user123 " } ) ;
if ( decision . isDenied ()) {
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { fixedWindow } from " @arcjet/sveltekit " ;
import { error , json , type RequestEvent } from " @sveltejs/kit " ;
// Define a custom userId characteristic.
// See https://docs.arcjet.com/architecture#custom-characteristics
characteristics : [ " userId " ] ,
export async function GET ( event : RequestEvent ) {
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( event , { userId : " user123 " } ) ;
if ( decision . isDenied ()) {
return error ( 429 , { message : " Too many requests " } ) ;
return json ( { message : " Hello world " } ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { fixedWindow } from " @arcjet/sveltekit " ;
import { error , json } from " @sveltejs/kit " ;
// Define a custom userId characteristic.
// See https://docs.arcjet.com/architecture#custom-characteristics
characteristics : [ " userId " ] ,
export async function GET ( event ) {
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( event , { userId : " user123 " } ) ;
if ( decision . isDenied ()) {
return error ( 429 , { message : " Too many requests " } ) ;
return json ( { message : " Hello world " } ) ;
import arcjet , { fixedWindow } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
// Define a custom userId characteristic.
// See https://docs.arcjet.com/architecture#custom-characteristics
characteristics : [ " userId " ] ,
export default async function handler ( req , res ) {
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( req , { userId : " user123 " } ) ;
if ( decision . isDenied ()) {
return res . status ( 429 ) . json ( { error : " Too Many Requests " } ) ;
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { fixedWindow } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
// Define a custom userId characteristic.
// See https://docs.arcjet.com/architecture#custom-characteristics
characteristics : [ " userId " ] ,
export default async function handler (
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( req , { userId : " user123 " } ) ;
if ( decision . isDenied ()) {
return res . status ( 429 ) . json ( { error : " Too Many Requests " } ) ;
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { fixedWindow } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
// Define a custom userId characteristic.
// See https://docs.arcjet.com/architecture#custom-characteristics
characteristics : [ " userId " ] ,
export async function GET ( req : Request ) {
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( req , { userId : " user123 " } ) ;
if ( decision . isDenied ()) {
return NextResponse . json (
error : " Too Many Requests " ,
return NextResponse . json ( {
import arcjet , { fixedWindow } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
// Define a custom userId characteristic.
// See https://docs.arcjet.com/architecture#custom-characteristics
characteristics : [ " userId " ] ,
export async function GET ( req ) {
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( req , { userId : " user123 " } ) ;
if ( decision . isDenied ()) {
return NextResponse . json (
error : " Too Many Requests " ,
return NextResponse . json ( {
import arcjet , { fixedWindow } from " @arcjet/node " ;
import http from " node:http " ;
key : process . env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
// Define a custom userId characteristic.
// See https://docs.arcjet.com/rate-limiting/configuration#characteristics
characteristics : [ " userId " ] ,
const server = http . createServer ( async function ( req , res ) {
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( req , { userId : " user123 " } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isDenied ()) {
res . writeHead ( 429 , { " Content-Type " : " application/json " } ) ;
JSON . stringify ( { error : " Too Many Requests " , reason : decision . reason } ) ,
res . writeHead ( 200 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { message : " Hello world " } )) ;
import arcjet , { fixedWindow } from " @arcjet/node " ;
import http from " node:http " ;
key : process . env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
// Define a custom userId characteristic.
// See https://docs.arcjet.com/rate-limiting/configuration#characteristics
characteristics : [ " userId " ] ,
const server = http . createServer ( async function (
req : http . IncomingMessage ,
res : http . ServerResponse ,
// Pass userId as a string to identify the user. This could also be a number
const decision = await aj . protect ( req , { userId : " user123 " } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isDenied ()) {
res . writeHead ( 429 , { " Content-Type " : " application/json " } ) ;
JSON . stringify ( { error : " Too Many Requests " , reason : decision . reason } ) ,
res . writeHead ( 200 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { message : " Hello world " } )) ;
import { ARCJET , type ArcjetNest , 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 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
// characteristics can also be set on the client in app.module.ts
characteristics : [ " userId " ] ,
. protect ( req , { userId : " user123 " } ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isRateLimit ()) {
HttpStatus . TOO_MANY_REQUESTS ,
throw new HttpException ( " Forbidden " , HttpStatus . FORBIDDEN ) ;
return this . pageService . message () ;
To identify users with different characteristics e.g. IP address for anonymous
users and a user ID for logged in users, you can create a custom fingerprint.
See the example in the custom characteristics
section .
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 , fixedWindow } from " @arcjet/nest " ;
import { Module } from " @nestjs/common " ;
import { ConfigModule } from " @nestjs/config " ;
//import { AppController } from './app.controller.js';
//import { AppService } from './app.service.js';
envFilePath : " .env.local " ,
key : process . env . ARCJET_KEY ! ,
// Applies to every request
//controllers: [AppController],
//providers: [AppService],
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 , fixedWindow } 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.
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 , 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 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
if ( decision . isDenied ()) {
if ( decision . reason . isRateLimit ()) {
HttpStatus . TOO_MANY_REQUESTS ,
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 " ) ;
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 " ) ;
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
Arcjet provides a single protect
function that is used to execute your
protection rules. This requires a RequestEvent
property which is the event
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 rate limit rule by using
decision.isDenied()
and decision.reason.isRateLimit()
.
You can iterate through the results and check whether a rate limit was applied:
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
This example will log the full result as well as each rate limit 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
characteristics : [ " ip.src " ] ,
allow : [] , // "allow none" will block all detected bots
fetch : aj . handler ( async ( 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 ()) {
if ( decision . reason . isRateLimit ()) {
return new Response ( " Too many requests " , { status : 429 } ) ;
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
characteristics : [ " ip.src " ] ,
allow : [] , // "allow none" will block all detected bots
fetch : aj . handler ( async ( 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 ()) {
if ( decision . reason . isRateLimit ()) {
return new Response ( " Too many requests " , { status : 429 } ) ;
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 ! ,
// Tracking 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 ,
// Tracking 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 ,
// Tracking 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 ! ,
// Tracking 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 " ;
// Tracking by ip.src is the default if not specified
//characteristics: ["ip.src"],
allow : [] , // "allow none" will block all detected bots
export async function GET ( event : RequestEvent ) {
const decision = await aj . protect ( event ) ;
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 " ;
// Tracking by ip.src is the default if not specified
//characteristics: ["ip.src"],
allow : [] , // "allow none" will block all detected bots
export async function GET ( event ) {
const decision = await aj . protect ( event ) ;
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/remix " ;
import type { LoaderFunctionArgs } from " @remix-run/node " ;
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
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 ()) {
if ( decision . reason . isRateLimit ()) {
throw new Response ( " Too Many Requests " , {
statusText : " Too Many Requests " ,
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
import arcjet , { fixedWindow , detectBot } from " @arcjet/remix " ;
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
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 ()) {
if ( decision . reason . isRateLimit ()) {
throw new Response ( " Too Many Requests " , {
statusText : " Too Many Requests " ,
throw new Response ( " Forbidden " , { status : 403 , statusText : " Forbidden " } ) ;
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 " } )) ;
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