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Forkbench vs Docker Sandboxes
Docker Sandboxes run coding agents such as Claude Code and Codex in isolated microVMs, locally for free or in Docker's cloud by the hour.
Updated
Docker Sandboxes run each agent inside a microVM. Forkbench boxes agents in natively: the macOS kernel keeps every agent in a Thread inside the folders you pick, with no VM to manage, then adds what a sandbox alone cannot: keys agents never read, a live view of who is working or stuck, human sign-off and sharing one job with anyone.
A sandbox answers one question: what can the agent touch? Forkbench answers that and the three that come right after it: what can it read of my secrets, what is it doing right now, and who decides it is done?
| Forkbench | Docker Sandboxes | |
|---|---|---|
| Agents locked to your project folders | Yes. The macOS kernel seals off the rest of your home folder, per Thread | A microVM per sandbox |
| API keys the agent never sees | Yes. The Vault runs the command and the agent only gets the result | Environment isolation, no secrets broker |
| Every agent at a glance | Yes. A live pulse on every tab and the task each agent claimed | Via the sbx CLI |
| Know when an agent is stuck | Instantly. It turns red and the Thread counts who needs you | Via the CLI |
| Share one job with a teammate or client | Yes. Invite them to one Thread, never your machine | No |
| Human sign-off before work counts as done | Always. Agents report, only you accept | No |
| Works with | Any CLI agent: Claude Code, Codex, Cursor CLI, Gemini CLI, Aider, your own scripts | Claude Code, Codex, Cursor, Copilot CLI and more |
| Platform | Desktop app, on your machine | macOS, Windows, Linux |
| Price | Free | Local free; cloud about $0.07/hour |
Why developers pick Forkbench
- A native kernel boundary in one click, with your real tools and builds.
- A free Vault: isolation does not stop a key in the environment from leaking, the Vault does.
- Supervision, a needs-you flag and sign-off for every agent.
- Share one job with a teammate or client.
What Docker Sandboxes does well
- A full microVM per agent, the stronger boundary for untrusted code.
- Cross-platform, with a cloud option when you want agents off your machine.
The verdict
Docker Sandboxes' cloud microVMs make sense when you want agents running fully off your own machine, billed by the hour. Running your own agents on your own box is a different job: Forkbench's kernel folder lock gives you a file boundary natively, with nothing to spin up, plus the Vault, the live view of every agent and the sign-off a sandbox alone leaves out.
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Comparison based on publicly available information, checked on the date above. Spot something out of date? Tell us.