User-Agent Router - Shared application layer that serves the same information to Agents, Crawlers, Humans, and APIs

A template for building agent-friendly Cloudflare Workers from first principles, without many dependencies, in the most minimal way possible.

Stack:

• Cloudflare Worker WinterTC Syntax in Typescript but allowing JS
• Vanilla HTML with inline Tailwind or vanilla CSS
• Server-side rendering
• Vanilla JS

Philosophy

The reason I built this is that I feel most of the web today is built on legacy standards and frameworks, and I wanted to show a different way. The most important fact that is the root for the choices that I've made, is that we don't need to serve just 1 format for any page, but we need to serve:

• structured data for apis
• markdown for agents
• html for SEO crawlers and humans
• og-image for social media

This template implementation shows how to do this in a way that makes intuitive sense, adhering to the accept and user-agent headers properly, serving the right format to the right client, while still allowing easy testing by changing the extension in the path.

I think this could be a great starting point to build a framework that goes back to basics, serving: JS, HTML, CSS, JSON, and PNG, all from a Cloudflare worker.

Benefits

• Shared application layer that serves the same information to agents, crawlers, humans, and APIs
• Developer-friendly: intuitive and accessible paths for easy testing.

See also

• X thread: https://x.com/janwilmake/status/1904951203340967987
• Hackernews thread: https://news.ycombinator.com/item?id=43484770
• Related work:
  • Sponsorflare - https://github.com/janwilmake/cloudflare-sponsorware
  • OpenAPI Search - https://x.com/janwilmake/status/1903405851286618501
  • l402 - https://x.com/janwilmake/status/1899454114523738206