@arcjet/deno

@arcjet/deno

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

This is the Arcjet SDK for Deno.

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

What is this?

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

When should I use this?

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

Install

This package is ESM only. Install with Deno:

deno install npm:@arcjet/deno

Use

import "jsr:@std/dotenv/load";
import arcjet, { shield } from "npm:@arcjet/deno";

// Get your Arcjet key at <https://app.arcjet.com>.
// Set it as an environment variable instead of hard coding it.
const arcjetKey = Deno.env.get("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" }),
  ],
});

Deno.serve(
  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" });
  }),
);

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)