Sandbox0

You register and authenticate with the s0 CLI, using device login, teams and scoped API keys, then create sandboxes through the CLI, the API or the open-source SDKs. Agent harnesses such as Codex, Claude Code or Cursor can drive the same CLI with no dedicated plugin.

While a task runs, the agent works inside a full system: it can install tools in /usr/local, change configuration in /etc and keep data under /home or /workspace. When the task ends, you pause. The writable RootFS is checkpointed and compute is released, so a paused sandbox incurs storage charges only. An idle sandbox left running still accrues compute.

When the next task arrives you resume explicitly or through automatic wake-up on supported access paths. Fresh compute attaches the committed RootFS and fetches blocks as the workload reads them. Default resume preserves files and starts fresh processes.

• •Persistent RootFS - The entire writable root filesystem, including system files, tools and user data, is kept across successful checkpoints. Each user gets an environment their agent can come back to.
• •Automatic online growth - Growth-enabled templates expand the root filesystem as free space runs low, within a configured device limit. The agent keeps running with the same paths and open files.
• •Incremental pause and resume - Checkpoints save the changed blocks and reuse the rest. Paused sandboxes are unlimited per team and do not count toward the default limit of 20 running at once.
• •Files while paused - You can read and inspect persistent files without waking compute. During a filesystem-only pause you can also edit, create, move and delete files through the same API and SDK methods.
• •Agent-native tooling - The s0 CLI covers sandboxes, commands, files, services, templates, snapshots, logs and metrics. Docs are also published as /llms.txt and raw markdown for agents to read.

Sandbox0 is built for developers of AI agent products who need to give every user an isolated, long-lived environment, such as coding agents that install dependencies and run tests, or assistants that keep files and configuration between sessions. Teams whose agents sit idle between tasks are the clearest fit, since pausing stops compute charges while keeping state.

It also suits developers who drive infrastructure from an agent harness or code, since the s0 CLI and SDKs are the main interface. Self-hosting and Bring Your Own Cloud are not available today.