arcjet js

Arcjet JS SDKs. Bot detection, rate limiting, email validation, attack protection, data redaction for Node.js, Next.js, Deno, Bun, Remix, SvelteKit, NestJS.

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Arcjet - JS SDK

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Arcjet helps developers protect their apps in just a few lines of
code. Implement rate limiting, bot protection, email verification, and defense
against common attacks.

This is the monorepo containing various Arcjet open source packages
for JS.

Quick start

Get help

Join our Discord server or reach out for support.

Examples

Example app

Try an Arcjet protected app live at https://example.arcjet.com
(source code).

Usage

Read the docs at docs.arcjet.com.

Next.js rate limit example

The Arcjet rate limit example below
applies a token bucket rate limit rule to a route where we identify the user
based on their ID e.g. if they are logged in. The bucket is configured with a
maximum capacity of 10 tokens and refills by 5 tokens every 10 seconds. Each
request consumes 5 tokens.

See the Arcjet Next.js rate limit documentation
for details.

import arcjet, { tokenBucket } from "@arcjet/next";
import { NextResponse } from "next/server";

const aj = arcjet({
  key: process.env.ARCJET_KEY!, // Get your site key from https://app.arcjet.com
  characteristics: ["userId"], // track requests by a custom user ID
  rules: [
    // Create a token bucket rate limit. Other algorithms are supported.
    tokenBucket({
      mode: "LIVE", // will block requests. Use "DRY_RUN" to log only
      refillRate: 5, // refill 5 tokens per interval
      interval: 10, // refill every 10 seconds
      capacity: 10, // bucket maximum capacity of 10 tokens
    }),
  ],
});

export async function GET(req: Request) {
  const userId = "user123"; // Replace with your authenticated user ID
  const decision = await aj.protect(req, { userId, requested: 5 }); // Deduct 5 tokens from the bucket
  console.log("Arcjet decision", decision);

  if (decision.isDenied()) {
    return NextResponse.json(
      { error: "Too Many Requests", reason: decision.reason },
      { status: 429 },
    );
  }

  return NextResponse.json({ message: "Hello world" });
}

Node.js bot protection example

The Arcjet bot protection example below will
return a 403 Forbidden response for all requests from clients we are sure are
automated.

See the Arcjet Node.js bot protection documentation for
details.

import arcjet, { detectBot } from "@arcjet/node";
import http from "node:http";

const aj = arcjet({
  key: process.env.ARCJET_KEY!, // Get your site key from https://app.arcjet.com
  rules: [
    detectBot({
      mode: "LIVE", // will block requests. Use "DRY_RUN" to log only
      // configured with a list of bots to allow from
      // https://arcjet.com/bot-list
      allow: [], // "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);
  console.log("Arcjet decision", decision);

  if (decision.isDenied()) {
    res.writeHead(403, { "Content-Type": "application/json" });
    res.end(JSON.stringify({ error: "Forbidden" }));
  } else {
    res.writeHead(200, { "Content-Type": "application/json" });
    res.end(JSON.stringify({ message: "Hello world" }));
  }
});

server.listen(8000);

Packages

We provide the source code for various packages in this repository, so you can
find a specific one through the categories and descriptions below.

SDKs

Analysis

Utilities

Internal development

Support

This repository follows the Arcjet Support Policy.

Security

This repository follows the Arcjet Security Policy.

License

Licensed under the Apache License, Version 2.0.