Cloudflare’s Kitesurf Is a Browser Built for AI Agents, Running on Workers

Cloudflare has built its own browser for AI agents. Kitesurf runs entirely on top of Cloudflare Workers and is available free, with per-account limits, while in beta in Browser Run, the company’s headless browser automation API, according to Cloudflare’s announcement.

A browser for agents doesn’t need themes, tabs or extensions, Cloudflare said, as TechCrunch reported. It needs to manage context windows, performance, token costs and scale, and it faces a different threat model.

How it’s built

Cloudflare decided to build Kitesurf 12 weeks before the launch, with the first commit in May. It draws on open-source Rust projects: parts of Blitz, a modular rendering engine, and Stylo, Firefox’s CSS parser, handle HTML and CSS parsing. Boa, a Rust ECMAScript engine, runs the occasional eval calls that Workers doesn’t support natively, and Cloudflare plans to drop it once native eval lands. The first proof of concept was a port of Obscura, an open-source Rust headless engine.

Kitesurf passes more than 215,000 Web Platform Tests, and Cloudflare says hundreds more pass each week. It also runs multistep Puppeteer tests against real websites in both Chromium and Kitesurf. Today it correctly renders TodoMVC, Wikipedia, Hacker News, the Cloudflare Blog and much of the Cloudflare dashboard.

Cost versus speed

In Cloudflare’s benchmarks across a 14-URL set, Chromium finished about 1.7x faster, mostly because of rasterization and image encoding. Kitesurf used 3 to 7 times less memory and CPU, which Cloudflare said “actually drive your bill.” Less memory means more sessions per machine.

Developers can point existing Puppeteer, Playwright or chrome-remote-interface clients, or any agent that speaks MCP and CDP, at Browser Run’s CDP endpoint and add a browser=kitesurf parameter. The same parameter works with Browser Run Quick Actions, such as screenshots.

What it can’t do yet

Cloudflare says Kitesurf isn’t the right choice for playing video, rendering WebGL, passing bot challenges that need real TLS fingerprints or running long authenticated sessions with persistent state. For those jobs, Browser Run’s default Chromium engine still applies.