arcjet-js

arcjet/arcjet-js is an open-source project by arcjet: Runtime security for AI apps and agents: prompt injection detection, tool-call authorization, sensitive-data redaction, bot protection, and rate limiting. Drop it into your JS/TS code.. Indexed here so it can be found — not resold.

It is free. Get it from the upstream repository: https://github.com/arcjet/arcjet-js

From the project's own README (excerpt, reproduced for discovery under its Apache-2.0 license):

Arcjet - JS SDK

[Arcjet][arcjet] is the runtime security platform that ships in your AI code. Detect prompt injection, authorize agent tool calls, redact sensitive data, and block bots and abuse. Real-time security building blocks you call inside your app, before an action happens.

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

Why Arcjet?

Your app's AI features and agents take real actions, calling tools, reading data, hitting APIs. Arcjet runs inside that code and lets you enforce security on each action in real time, then audit what happened

Which package do I need?

Arcjet protects two types of entry points. Pick the right path for your use case:

Entry point When to use Package ---------------------- -------------------------------------------------------------------------------------------------------------- --------------------------------------------------- Request protection HTTP route handlers, API endpoints, middleware — anything with an incoming Request object. @arcjet/next, @arcjet/node, @arcjet/bun, etc. Guard protection AI agent tool calls, MCP server handlers, queue workers, background jobs — anything without an HTTP request. @arcjet/guard

Not sure? If you have an HTTP request, use a framework SDK. If you don't, use @arcjet/guard. You can use both in the same project.

Getting started

The fastest way to get started is with an AI coding agent. Log in, install a skill, and let your agent handle the rest.

Step 1: Log in with the CLI

You can also sign up and manage keys at app.arcjet.com, or connect the Arcjet MCP server to your AI assistant.

Step 2: Install a skill

Skills give your agent the documentation to detect your framework, install the SDK, and wire up request or guard…