@arcjet/bun

@arcjet/bun

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 Arcjet SDK for Bun.sh.

• npm package (@arcjet/bun)
• GitHub source code (arcjet-bun/ in arcjet/arcjet-js)

Getting started

Visit the quick start guide to get started.

Example app

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

What is this?

This is our adapter to integrate Arcjet into Bun. Arcjet helps you secure your Bun server. This package exists so that we can provide the best possible experience to Bun users.

When should I use this?

You can use this if you are using Bun. See our Get started guide for other supported runtimes.

Install

This package is ESM only. Install with Bun:

bun add @arcjet/bun

Use

import arcjet, { shield } from "@arcjet/bun";

// Get your Arcjet key at <https://app.arcjet.com>.
// Set it as an environment variable instead of hard coding it.
const arcjetKey = Bun.env.ARCJET_KEY;

if (!arcjetKey) {
  throw new Error("Cannot find `ARCJET_KEY` environment variable");
}

const aj = arcjet({
  key: arcjetKey,
  rules: [
    // Shield protects your app from common attacks.
    // Use `DRY_RUN` instead of `LIVE` to only log.
    shield({ mode: "LIVE" }),
  ],
});

export default {
  port: 8000,
  fetch: aj.handler(async function (request: Request) {
    const decision = await aj.protect(request);

    if (decision.isDenied()) {
      return Response.json({ message: "Forbidden" }, { status: 403 });
    }

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

For more on how to configure Arcjet with Bun and how to protect Bun, see the Arcjet Bun SDK reference on our website.

License

Apache License, Version 2.0 © Arcjet Labs, Inc.

Changelog

1.0.0-beta.12 (2025-09-22)

🚀 New Features

• add React Router integration (#5199) (498292e)
• analye-wasm, redact-wasm: ignore dashes in card numbers (#5210) (5c414d6)
• arcjet: add IP-related fields to filters (#5170) (d0aeb84)
• filters: add limit to 10 expressions, 1024 bytes (#5212) (502288a)
• stable-hash, transport: support workerd (#5077) (13c90d6)

🪲 Bug Fixes

• arcjet: show error about incorrect characteristics in logs (#5078) (9839c9c)
• astro: fix types, zod validation (#5052) (ea82f8f)
• examples: add styles to remix-express (#5115) (783db87)

📝 Documentation

• add JSDocs examples to filter rule (#5208) (c4e506a)

🧹 Miscellaneous Chores

• ci: Remove dependabot groups on examples and apply cooldown to direct deps (#5202) (9058a24)
• examples: remove experimental.nodeMiddleware from example (#5124) (408a26e)

📚 Tests

• astro: add tests (#5069) (e6d9980)