Cloudflare launches Sandboxes

Cloudflare said on April 13 that Sandboxes are now generally available, giving artificial intelligence agents persistent Linux machines to run code and keep state. (blog.cloudflare.com) A sandbox is a locked room for code: an isolated environment with its own shell, filesystem, and background processes. Cloudflare said an agent can use one to clone a repository, install packages, run builds, and return to the same session later. (blog.cloudflare.com) Cloudflare’s developer docs say each sandbox runs in a dedicated Linux container, keeps an isolated filesystem, and is addressed by a unique sandbox identifier. The company says developers can control those environments from Workers through its Sandbox software development kit. (developers.cloudflare.com) The release adds features aimed at coding agents, including pseudo terminal support for interactive command lines, built-in persistent interpreters for Python, JavaScript, and TypeScript, filesystem watching, snapshots, and live preview web addresses. Cloudflare also said it added secure credential injection so agents can make authenticated calls without directly handling secrets. (blog.cloudflare.com) Cloudflare is pairing Sandboxes with another new product called Dynamic Workers, which run shorter-lived JavaScript tasks in lightweight isolates instead of full containers. The company said Dynamic Workers start in milliseconds, while Sandboxes are for jobs that need a full operating system and longer-running state. (blog.cloudflare.com; morningstar.com) That split reflects a broader problem in artificial intelligence tooling: an agent can write code or plan steps in text, but many developer tasks still require a real machine to execute commands, install dependencies, and inspect failures. Cloudflare’s April 13 changelog said Containers and Sandboxes are both now generally available on Workers for those heavier workloads. (developers.cloudflare.com) Cloudflare first introduced Sandboxes as an experimental product on June 24, 2025, under the name “Code Sandboxes.” At the time, the company said it was using the product to test how isolated, container-like workloads could scale on its network. (developers.cloudflare.com) The company has been building out the surrounding tooling in recent months. In January, Cloudflare published Moltworker, a self-hosted personal agent built on the Sandbox software development kit, and later added identity-aware authentication for sandbox access. (blog.cloudflare.com; blog.cloudflare.com) Cloudflare’s pitch is that agents now need both kinds of computers: a fast disposable one for small code snippets, and a persistent one for full development loops. With Sandboxes now out of beta, the company is trying to make that second machine part of its Workers platform. (blog.cloudflare.com; blog.cloudflare.com)