Introducing Cloud Sandboxes: Start on Your Laptop, Finish in the Cloud
Docker ·
Run agents on your laptop, in the cloud, and move between them with one command, all safely. Earlier this year we launched Docker Sandboxes: microVM environments where coding agents can work autonomously in a safe way.
Run agents on your laptop, in the cloud, and move between them with one command, all safely. Earlier this year, we launched Docker Sandboxes: microVM environments where coding agents can work autonomously and safely.
Since then, agents have started taking on long-horizon work: tasks that run for hours, not minutes. Agents need a new place to work. Today, we’re introducing Cloud Sandboxes: the same microVM-based sandbox, running on Docker-managed compute, with one command to move between them.
The most important change in coding agents over the past year is that they can work for much longer. Tasks that used to need a developer checking in every few minutes (a large refactor, a dependency migration, a test suite that takes an hour) you can now hand off and review when they finish.
When agents worked in short bursts, the question was whether the model could hold a task together. Now that they work in hours, the question is where those hours happen. A laptop is built around a person. It sleeps when the lid closes, slows down on battery, and disconnects when you move. None of that matters for a task that takes thirty seconds. All of it matters for a task that takes all night.
We built Docker Sandboxes to answer the first question about agents: is it safe to run unattended? In Docker Sandboxes, agents run in a microVM with its own kernel and Docker daemon, isolated from your machine, so they can work autonomously while your files, network, and secrets are protected if an agent steps out of line.
Today, we’re introducing Cloud Sandboxes to answer the second question: how do I run a dozen agents at once, for five, ten, or 21 hours each, without watching any of them? Cloud Sandboxes is the same microVM, running on Docker-managed compute. The isolation model is identical. The CLI is identical. What changes is that the machines underneath are always on, and there are as many of them as you need.
Here’s what that means for you:
Close your laptop and keep the work going. Start an agent in the cloud before you leave for the day, disconnect, and review what they did in the morning.
Start local and move to the cloud when your task outgrows your laptop. Iterate with an agent on the code in front of you, then hand off long tasks and loops to a background agent.
$ sbx move my-project --to cloud
A move captures the sandbox’s filesystem and recreates it on the other side, so your work carries over. This works in both directions.
Run 100 tasks in parallel with nothing to provision. Docker runs the compute. You point your agents at it. Each one gets its own microVM, its own secrets, and its own network policy.
Try things cheaply. Run a pre-built agent for an hour to test an idea, then spin it down.
Agents that do long-horizon work without you need three things:
Cloud Sandboxes ship with all three. You can spin up and manage Cloud Sandboxes from the CLI or from the web console.
Kits. A kit is a pre-configured, pre-built sandbox for an agent. The leading coding agents are ready today, including Claude Code, Codex, Copilot, Antigravity, Open Code and Hermes. Or, you can easily add your own. It’s easy to spin up. sbx –cloud run codex starts one, for example.
MCP. Connect the MCP servers your agents need (Jira, Linear, Grafana, incident.io, or any streamable HTTP endpoint) once, and all your agents can reach them through a single gateway whether they’re running in the cloud, locally, or in other clients like the ChatGPT desktop app.
Secrets. Store keys or tokens once. Cloud Sandboxes proxy injects it per request, so agents don’t see the actual secret. Prompt injections can’t touch secrets your agents never had in the first place.
Policies. Set network policies on what endpoints agents can access by defining them once. Centralized governance is coming soon for enterprises through Docker AI Governance .
You can access and manage all of this through the web console.
We could have built Cloud Sandboxes as a separate product with its own commands. We didn’t, and the reason is simple: how much you can trust your agent shouldn’t depend on where it happens to be running.
As far as we know, no other agent sandbox works this way. We think the right answer to using agents is one strong isolation model that runs in both surfaces (locally and in the cloud), and an easy way (one command) to move between them.
These aren’t two tiers of one product. Interactive work belongs on your laptop. Work that takes hours belongs in the cloud. Most developers need both, and now you don’t have to pick.
Cloud Sandboxes are pay-as-you-go. We meter compute by the second, and nothing else. A paused sandbox costs nothing. Volumes, egress, and hosting public images and Kits are free. You can bring your own model key and keep your existing provider for inference.
Size
vCPUs
Memory
Per hour
Micro
2 GiB
$0.07
Small (default)
4 GiB
$0.14
Medium
8 GiB
$0.28
Large
16 GiB
$0.56
XL
16
32 GiB
$1.12
Sandboxes run for one hour by default and up to 24 hours per session.
From the browser: sign in to the web console , choose a kit, and click Run.
From the terminal:
$ brew install docker/tap/sbx $ sbx login $ sbx --cloud run claude
You’ll need sbx 0.45.1 or later and the pay-as-you-go plan, available on Docker Personal and Pro accounts. Docker Sandboxes on your laptop remain free and standalone, with no Docker Desktop required. Local and cloud sandboxes keep separate secrets, templates, and network policies, so read the differences in the docs before you move a local workflow.
For a limited time, new accounts get $250 in free Cloud Sandboxes credit. Claim it here .
We think the way software gets built is changing. Developers will spend less time typing and more time directing: handing agents real tasks, stepping back, and reviewing what comes back. For that to work, agents need environments that are safe enough to run unsupervised and durable enough to run for hours. That’s what Docker Sandboxes is for, and as of today, it runs on your laptop and in the cloud.
Start one before you close your laptop tonight.