Cloudflare Computer

Cloudflare Computer is a virtual filesystem that lives inside a Durable Object. The Durable Object holds the authoritative state in SQLite and exposes one pluggable execution surface through workspace.runtime. Three backends ship today:

• Container projects the SQLite state into a sandbox container as a real FUSE mount. A sandbox-side daemon (computerd) mounts the state as a filesystem and syncs changes back over a capnweb RPC channel. Full Linux userland, real binaries, real network.
• Isolate shell runs just-bash in a Dynamic Worker. It reaches the authoritative Workspace over Workers RPC, so there is no second store or sync round trip.
• Isolate JavaScript runs an ECMAScript module in a fresh Dynamic Worker with structured input/results, durable relative imports, configured libraries, Workspace-backed node:fs/promises, and trusted ws:git and ws:artifacts modules.

A Workspace may register multiple backends under stable IDs. workspace.runtime.exec(source, { backend }) is the single execution entry point; the selected backend defines whether source is a shell command or an ECMAScript module. Backends connect lazily on first use.

Workspace can also be constructed without a backend at all, giving callers the filesystem on its own.

Important

PREVIEW ONLY This package is provided as a preview for feedback only. APIs are unstable and the design is subject to change.

Suitable for experiments, exploration and prototypes. It is NOT suitable for production use at this time.

The specification under docs/ is forward-looking — read it for intent, not as description of the code today.

Using it

If you want to build on Cloudflare Computer, install @cloudflare/computer and follow that package's README — it has the installation steps, the entrypoint map, and worked examples of the fs and runtime surfaces.

To work on this repository itself, see CONTRIBUTING.md for setup, build, and test instructions.

Examples

The examples/ directory holds runnable consumers of the public surface. Each is a Worker workspace with its own README.

• examples/container — runs computerd inside a container, mounts a workspace, and talks to a Durable Object over capnweb. A write / read / exec HTTP surface.
• examples/worker-shell — same HTTP surface as the container example, but the shell runs just-bash in a Dynamic Worker loaded through env.LOADER. No container.
• examples/worker-javascript — mirrors worker-shell, but exec evaluates an ECMAScript module in a Dynamic Worker instead of running a shell command.
• examples/think — a @cloudflare/think chat agent that uses the workspace as its working directory, reachable from a terminal.
• examples/think-compare-runtimes — a web UI that runs the same agent task against the container and worker runtimes side by side.
• examples/tutorial — a step-by-step build: one endpoint, one agent that writes a markdown recipe card on the host and runs pandoc on it in the container to produce a PDF.
• examples/artifacts — generates a Worker project in a workspace and publishes it to Cloudflare Artifacts as a clone-ready repo.
• examples/assets — turns a prompt into an image with Workers AI, writes it to the workspace, and returns a shareable link through @cloudflare/computer/assets.

Repository layout

The repo is a small monorepo. Each package has its own README with package-specific status and usage notes.

• packages/dofs (@cloudflare/dofs) — Durable Object SQLite-backed virtual filesystem, sync protocol building blocks, and a @platformatic/vfs provider for Node.
• packages/rpc (@cloudflare/computer-rpc) — capnweb wire types and server/client helpers shared between the Durable Object and computerd.
• packages/computerd (@cloudflare/computerd) — the computerd daemon: a FUSE mount plus HTTP/WebSocket RPC server that runs inside the sandbox container.
• packages/computer (@cloudflare/computer) — the top-level Computer package consumed by Durable Objects. Work in progress.
• packages/computer-computerd-linux-x64 (@cloudflare/computer-computerd-linux-x64) — the prebuilt computerd binary for linux-x64, distributed for use in container images.

Performance

computerd's FUSE mount beats real disk on metadata-heavy work and trails it on large sequential I/O. See docs/19_performance.md for the full fs-bench numbers, a cloudflare/sandbox-sdk npm install comparison, and how to reproduce them.

Documentation

• docs/ — design specification. Forward-looking; treat as intent.
• docs/19_performance.md — filesystem benchmarks.

Contributing

See CONTRIBUTING.md for setup, formatting, testing, commit message, and pull request conventions.

If you're working in this repo as an agent, start with AGENTS.md and the skills under .agents/skills/.

License

MIT. See LICENSE.