Cloudflare open-sources Kitesurf agent browser
Cloudflare has released Kitesurf, its stateless browser for AI agents, under Apache 2.0, so developers can now run their own lightweight browser engine on their own Cloudflare accounts.
Cloudflare announced that Kitesurf is now open source on GitHub under the Apache 2.0 license. When it introduced the browser in August, the company promised to release the code. It added WebMCP support and new APIs in September.
Kitesurf runs entirely on Cloudflare Workers. It parses HTML, applies CSS, executes page JavaScript and renders screenshots without a browser container. It also supports the Chrome DevTools Protocol, so clients such as Puppeteer can connect to it. Cloudflare says Kitesurf is meant to let agents load and interact with pages while using less CPU and memory than a full browser like Chromium.
The engine is built from open-source Rust packages compiled to WebAssembly:
- Blitz handles HTML parsing, the DOM, layout and painting.
- Stylo handles CSS.
- Boa runs JavaScript, but only as a fallback when Dynamic Workers can't.
- Linebender libraries handle text layout and 2D graphics.
- Krilla produces PDF output.
The system has three parts. The Engine manages sessions and client connections, PageScript runs the page and its JavaScript, and PageRenderer draws the result.
Developers can run Kitesurf locally through a wrangler dev server or deploy it to their own account in place of Cloudflare's managed Browser Run APIs. Self-hosting requires a Workers Paid plan, because Kitesurf uses Dynamic Workers to create an isolated Worker for each page.
Cloudflare says the project is under heavy development, with its current focus on compatibility, reliability and efficiency. It points to Web Platform Tests results to track compatibility. Contributors must open an issue and be vouched for by a maintainer before submitting a pull request. The post includes no benchmark figures.