Nimbus documentation

Nimbus is an open-source, POSIX-like sandbox that runs on Cloudflare Durable Objects. Each sandbox is a real shell with node, python, ruby, git, npm, and clang — no containers, no VMs. Sessions boot in ~0.6 s median, cost nothing while idle, and keep a 10 GB persistent disk.

QuickstartSandbox APIGitHub

Live sandbox

The terminal below is a live sandbox, created on demand when it scrolls into view — a real session on the hosted deployment, the same thing the SDK creates. Anonymous sessions last 10 minutes and are capacity-limited; if none are available, retry in a minute.

nimbus — live sandbox

Live sandbox — connecting…

Documentation

Getting started

Start a session, run real commands, and see where Nimbus sits among other sandboxes.

• Quickstart
• Where Nimbus fits

The sandbox

What a session provides: shell, disk, toolchains, git, processes, and the session agent.

• Terminal & shell
• The disk
• Toolchains & packages
• Git
• Processes & servers
• The session agent

SDK

Deploy Nimbus to a Cloudflare account and drive sandboxes from code.

• Embed Nimbus in a Worker
• Configure the handler
• The sandbox API
• Tokens & auth

Internals

How the system works: the supervisor and facets, the SQLite disk, processes, routing, and WASI.

• The fabric
• Inside the disk
• The process fabric
• Ports & routing
• WASI & syscalls

Status & limits

Capability claims backed by live probes, measured benchmarks, and open research.

• Capabilities & limits
• Benchmarks
• Research & roadmap

Nimbus is MIT-licensed and in alpha. Every capability claim is verified against a live session by behavioral probes; Capabilities & limits states what works, what is partial, and what is not supported.