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brownstone-middleware

v0.1.4

Published

Express middleware for detecting, logging, and enforcing licensing around AI agent access

Vulnerabilities

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Links

Maintainers

pettygpettyg

Keywords

ailicensingmiddlewareexpressbot-detectioncrawlers

Readme

brownstone-middleware

Express middleware for detecting, logging, and enforcing licensing around AI agent access to your application.

Brownstone identifies AI crawlers and bots by their user-agent, injects licensing metadata into your HTML responses, and optionally logs hits and blocks unauthorized AI access — all in a few lines of code.

Install

npm install brownstone-middleware

Usage

const express = require("express");
const brownstone = require("brownstone-middleware");

const app = express();

app.use(
  brownstone({
    apiKey: "your-brownstone-api-key",
    metering: true,
    enforcement: true,
    license: {
      model: "paid",
      rate: "$0.001-per-1000-tokens",
      permission: "allowed",
    },
  }),
);

app.get("/", (req, res) => {
  res.send("<html><head></head><body>Hello</body></html>");
});

How it works

  1. Each incoming request is checked for a known AI user-agent
  2. If an AI is detected and metering is enabled, the hit is logged to your Brownstone dashboard. Unknown bots (user-agents matching generic patterns like bot, crawler, spider, or scraper) are also logged.
  3. If enforcement is enabled, the request is checked against your site's license — blocked AIs receive a 403 response
  4. A <meta name="ai-usage"> tag is injected into every HTML response so AI crawlers can read your licensing terms directly from the page

Options

| Option | Type | Required | Description | | -------------------- | ------- | ---------------------------------------- | --------------------------------------------------------------------------- | | apiKey | string | Yes (if metering or enforcement enabled) | Your Brownstone site API key | | apiUrl | string | No | Base URL of the Brownstone API (default: https://api.brownstoneai.dev) | | metering | boolean | No | Log AI and unknown bot hits to the Brownstone API | | enforcement | boolean | No | Block AIs based on your site's configuration | | llmsTxt | string | No | Custom content to serve at /llms.txt | | license | object | No | License info injected into HTML meta tag | | license.model | string | No | "free" or "paid" | | license.rate | string | No | e.g. "$0.001-per-1000-tokens" | | license.permission | string | No | "allowed", "restricted", or "blocked" |

Detected AI agents

Brownstone detects the following bots out of the box:

  • ChatGPT (OpenAI)
  • OpenAI Training Crawler (GPTBot)
  • Claude (Anthropic)
  • BingAI (Microsoft)
  • Perplexity
  • Gemini (Google)
  • Grok (xAI)
  • Meta AI
  • Common Crawl
  • Cohere
  • Diffbot
  • Bytespider (ByteDance)
  • YouBot
  • AppleBot
  • DuckAssist (DuckDuckGo)
  • Amazonbot

Get an API key

Register your site and get an API key at brownstoneai.dev or by running the Brownstone API locally.

License

MIT