Cloudflare announced Kitesurf, a new web browser that runs entirely on the Workers platform and is designed specifically for AI agents and automation applications. Kitesurf is currently available for free during the beta through the Browser Run product, with account-level usage limits.
Cloudflare says traditional browsers such as Chromium were primarily built for human needs, and therefore include capabilities and resource consumption that models and agents do not necessarily need. Kitesurf instead focuses on machine-readable content, token size, context capacity, scalability, performance, and cost, while accepting some compromises in visual-rendering accuracy.
A Browser Focused on Agents’ Needs
An AI agent typically does not need tabs, visual attributes, extensions, or cross-device synchronization, but it does need to extract HTML, capture screenshots, and handle web pages at scale and low cost. Security requirements also differ when an agent interacts with untrusted pages and sources, making risks such as prompt injection and tool safety priorities.
Development of Kitesurf began 12 weeks before the announcement, taking advantage of developments in Cloudflare’s developer platform, including the maturation of WebAssembly execution inside Workers, dynamic isolates, SQLite-backed Durable Objects, RPC between Workers, Service Bindings, improved Node.js compatibility, and higher operational limits.
Isolated, Stateless Architecture
Kitesurf consists of three main components: Engine, PageScript, and PageRenderer. Engine is the only publicly exposed component; it handles the REST HTTP and WebSocket interfaces for the Chrome DevTools Protocol and stores session state. The remaining components are as stateless as possible, allowing them to be restarted or discarded upon failure and scaled on demand.
The SandboxOutbound worker handles all internet connections, while the other components are prevented from accessing the network directly through Dynamic Workers. This component applies CORS policies, adds browser-like headers, filters responses, isolates cookies for each page, and rejects policy-violating requests with a 403 code.
PageScript uses separate, out-of-process isolates for each page or iframe and uses parts of Blitz and the Rust-written Stylo CSS parser. PageRenderer converts computed page objects into frames that the client can render in formats such as JPEG and PNG, or as PDF. To handle failures, the system is designed so that an error results in an empty frame or a missing element rather than bringing down the entire session.
Test and Performance Results
Kitesurf currently passes more than 215,000 Web Platform Tests, with hundreds of successful tests added each week. Strong coverage includes agent-relevant areas such as CSS, DOM, HTML, selection, SVG, and XHR.
In a comparison involving five median runs of fast operations through Browser Run, across a set of 14 URLs, Kitesurf used approximately 380 milliseconds of CPU to capture a screenshot, compared with 1,173 milliseconds for Chromium, and used 229 milliseconds to extract HTML compared with 877 milliseconds. Memory usage was 57.8 MiB for screenshot capture and 39.4 MiB for HTML extraction, compared with 271 and 273.7 MiB, respectively, for Chromium.
By contrast, Chromium was faster in total elapsed time: 637 milliseconds for screenshot capture compared with 1,148 milliseconds for Kitesurf, and 472 milliseconds for HTML extraction compared with 820 milliseconds. Cloudflare attributes this difference to Chromium’s JIT advantage and the cost of software rendering and encoding, while it considers the three- to seven-fold reduction in memory and CPU consumption in the cited tests more relevant to operating costs and scalability.
Availability and Limitations
Kitesurf can be used through the CDP endpoint in Browser Run by adding the browser=kitesurf parameter. It also works with Puppeteer, Playwright, chrome-remote-interface, and agent tools that use MCP and CDP. It is also available through Quick Actions, in addition to a public Playground that enables testing URLs and inspecting the DOM, console messages, network activity, and WebAssembly consumption.
Kitesurf is suitable for agents that need to render pages, extract their content, create PDFs, or capture screenshots, while accepting that it is not fully compatible with the Chromium browser. However, it does not currently support video playback or WebGL, or handling robot-challenge handshakes through real TLS fingerprints. It is also not suitable for long-lived authenticated sessions that require persistent state. Cloudflare recommends testing the target site through Kitesurf interfaces or the Playground, with the option of using the default Chromium-based Browser Run when needed.
Cloudflare is working to expand CDP coverage, improve rendering accuracy for screenshots and PDFs, increase WPT test compatibility, and reduce CPU, memory, and total elapsed time. The company said it plans to open-source Kitesurf when it is ready, enabling customers to deploy their own versions on their accounts.