boat vs Docker Cloud Sandboxes
Both give each coding agent its own small Linux VM with Docker inside. boat's machine can run for weeks, has a desktop and browser, and lets you drive the agent inside from outside, while Docker's is the same microVM you already run on your laptop, now in the cloud.
Where boat stands out
Runs as long and as wide as the work
A boat sandbox has no session cap on paid plans, and the $20 plan runs 100 at once. Docker ends a sandbox 24 hours after creation and allows 10 at a time by default, with no published way to ask for more.
A whole machine, screen included
boat exposes /dev/kvm for Android emulators and VMs, and every sandbox has a 60fps Linux desktop with Chromium for computer use. Docker's cloud sandboxes are terminal sessions with Docker inside, and its docs do not offer nested virtualization or a desktop.
Drive agents inside from outside
Claude Code, Codex and five other agents come preinstalled, and you prompt, steer and follow them through one API with structured events. Docker starts agents for you too, but you reach them by attaching to their terminal from the sbx CLI.
The companies and products
boat
boat.dev runs sandboxes for AI agents: each one is a full Linux VM with its own kernel.
You start a machine with one command or one API call, then SSH in, run Docker, open a desktop, or let a built-in agent (Claude Code, Codex, OpenCode and others) work in it. The disk stays between sessions, and a stopped sandbox costs nothing.
- Isolation
- Full VM per sandbox, own kernel
- Regions
- EU: Germany, Finland, France
Docker Cloud Sandboxes
Docker Cloud Sandboxes runs Docker's sbx coding-agent microVMs on Docker-managed compute instead of your laptop.
Each sandbox is a microVM with its own Linux kernel and its own Docker Engine, started from the same sbx CLI you use locally, with Claude Code, Codex and other agents ready to run. You can move a sandbox from your laptop to the cloud and back, publish HTTPS ports and SSH in. It launched on September 24, 2026, is billed pay-as-you-go on a personal Docker account, and is built for developers who want their local agent sandboxes to keep going off their machine.
- Launched
- September 24, 2026
- Session length
- 1 hour by default, extendable to 24 hours from creation
- Default quota
- 10 concurrent and 50 stored sandboxes per account
- Regions
- Not published
Which use cases each one fits
For each use case, Battleships prices every sandbox provider on the same workload and sorts them from the cheapest monthly bill up. “3rd cheapest of 367” means 2 of the other 366 providers run that workload, with every feature it needs, for less. “With limits” means the provider runs it but misses something, so it is listed after every full match. Open a use case for its whole ranking and what each provider misses.
| Use case and its workload | boat: price rank | Docker Cloud Sandboxes: price rank |
|---|---|---|
| Software factory 100 at once · 4 vCPU / 8 GB · 2,200 sessions of 8 h a month A software factory runs agents for days and many at once; Docker stops each sandbox at 24 hours and allows 10 at a time by default. | 3rd cheapest of 367 $634 a month | 280th of 367, with limits $4,928 a month |
| Always-on AI employees 50 machines 24/7 · 2 vCPU / 4 GB An assistant that lives on its machine all month cannot do it in one Docker session, which ends 24 hours after creation. | 5th cheapest of 366 $657 a month | 276th of 366, with limits $5,110 a month |
| Code interpreter bursts 100 at once · 1 vCPU / 2 GB · 200,000 sessions of 1 min a month Docker fits short code runs a little better here: small sandboxes billed by the second, stopped with their memory between runs. | 186th of 345, with limits $2,000 a month | 119th of 345, with limits $233 a month |
| Sandboxes for your users 300 at once · 2 vCPU / 4 GB · 30,000 sessions of 23 min a month Serving your own users needs more than Docker's default 10 concurrent sandboxes, and its plan sits on one personal account. | Cheapest of 361 $209 a month | 136th of 361, with limits $1,628 a month |
| RL rollouts 1,000 at once · 2 vCPU / 4 GB · 1,000,000 sessions of 3 min a month | 34th of 360, with limits $2,000 a month | 114th of 360, with limits $7,000 a month |
| Agent evals 250 at once · 4 vCPU / 8 GB · 15,000 sessions of 20 min a month | 10th cheapest of 364 $200 a month | 167th of 364, with limits $1,400 a month |
| CI runners 40 at once · 8 vCPU / 16 GB · 6,000 sessions of 12 min a month CI that builds Android apps or VM images needs /dev/kvm, which boat exposes and Docker's docs do not offer. | 4th cheapest of 377 $86 a month | 172nd of 377, with limits $672 a month |
| 24/7 dev boxes 1 machine 24/7 · 4 vCPU / 8 GB A dev box that stays on all month needs no session cap; Docker's sandboxes end 24 hours after creation. | 18th cheapest of 368 $26 a month | 127th of 368, with limits $204 a month |
| Computer-use agents 50 at once · 4 vCPU / 8 GB · 20,000 sessions of 15 min a month Computer-use agents need a screen; boat has a 60fps Linux desktop with Chromium, while Docker's sandboxes are terminal only. | 6th cheapest of 369 $200 a month | 268th of 369, with limits $1,400 a month |
| Browser-use agents 50 at once · 2 vCPU / 4 GB · 30,000 sessions of 10 min a month Browser agents need a real browser inside the machine, which boat ships and Docker does not. | 7th cheapest of 367 $200 a month | 277th of 367, with limits $700 a month |
| Scraping & bots (startup scale) 50 at once · 1 vCPU / 2 GB · 100,000 sessions of 3 min a month | 6th cheapest of 346 $90 a month | 262nd of 346, with limits $350 a month |
| Mass scraping & bots (undetectable) 1,000 at once · 1 vCPU / 2 GB · 3,000,000 sessions of 2 min a month | 71st of 338, with limits $1,800 a month | 190th of 338, with limits $7,000 a month |
| Parallel red teaming 200 at once · 2 vCPU / 4 GB · 5,000 sessions of 30 min a month | 2nd cheapest of 360 $200 a month | 248th of 360, with limits $350 a month |
| GPU eval jobs 10 at once · 8 vCPU / 32 GB · 500 sessions of 30 min a month | Can't run it | Can't run it |
| macOS agents 5 at once · 4 vCPU / 8 GB · 1,000 sessions of 20 min a month | Can't run it | Can't run it |
Key features
| Feature | boat | Docker Cloud Sandboxes |
|---|---|---|
| Isolation | Full VM with its own kernel on dedicated AMD Ryzen 9 9950X hosts | MicroVM with its own Linux kernel; hypervisor not named |
| Session length | No cap on paid plans; you set the time to live | 1 hour by default, at most 24 hours from creation; resuming starts a new timer |
| Sandboxes at once | 100 on the $20 plan, up to 2,000 on higher plans, self-serve | 10 by default; no published way to raise it |
| Stop and resume | Disk saved every minute and on stop; resume boots the machine again | Stop keeps memory and files; resume picks up where it left off |
| Fork | Fork a running sandbox with its disk | Snapshot a running sandbox with disk or disk and memory, then restore it as a new sandbox |
| Docker inside | Yes, with root and systemd | Yes, its own Docker Engine; agent runs as a non-root user with sudo |
| Nested virtualization | Yes, /dev/kvm for Android emulators and VMs | Not documented |
| Desktop and browser | 60fps Linux desktop with Chromium and computer use | Terminal sessions only |
| Inbound access | HTTPS URLs for up to 50 ports, token-protected by default; raw TCP; dedicated IPv4 or IPv6 | Public HTTPS URL per published port, not protected by Docker sign-in; not a TCP tunnel; SSH with Docker-issued certificates |
| Outbound rules | Open internet, no provider-side allowlist | Allow and deny rules by host, with allow-all, balanced and deny-all presets |
| Coding agents | Seven agents preinstalled, with a prompt, steer and events API to drive them from outside | Claude Code, Codex, Copilot, OpenCode and more, run and attached to from the sbx CLI |
| Keeping API keys out of the sandbox | Credentials proxy for model providers and any HTTPS API; switch a credential to another account when credits run out | Cloud proxy sets the auth header for built-in AI services and custom hosts; the sandbox sees a placeholder |
| Laptop and cloud | Cloud only | Same microVM and CLI locally or in the cloud; move a sandbox either way |
| Regions | EU only (Germany, Finland, France) | Not published |
| Compliance and transparency | SOC 2 is in progress. We're open about where we stand: live status and data retention policy. | No SOC 2 report published |
Every feature Battleships tracks (43)
| Feature | boat | Docker Cloud Sandboxes |
|---|---|---|
| Full VM (own kernel) | Yes | Yes |
| Docker inside | Yes | Yes |
| Nested virtualization | Yes | No |
| Root | Yes | Yes |
| Systemd | Yes | Not published |
| Desktop GUI | Yes | No |
| Browser | Yes | No |
| Computer-use API | Yes | No |
| SSH | Yes | Yes |
| Persistent disk | Yes | Yes |
| Pause/resume | Yes | Yes |
| Automatic snapshots | Yes | Yes |
| Fork/clone | Yes | Yes |
| Live fork (no pause) | Yes | Yes |
| Memory fork | No | Yes |
| Custom image (Docker or snapshot) | Yes | Yes |
| ≥24 h sessions | Yes | Yes |
| Idle auto-stop | No | No |
| Wake on request | No | Not published |
| HTTPS preview URLs | Yes | Yes |
| Raw TCP inbound | Yes | Not published |
| Public IPv4 | No | No |
| Egress allowlist | No | Yes |
| Secret proxy | Yes | Yes |
| Secret proxy for any API | Yes | Yes |
| Preinstalled agents | Yes | Yes |
| Agent harness API | Yes | No |
| MCP server | No | Yes |
| GPU | No | No |
| Windows | No | No |
| Arm64 | No | Yes |
| Self-hosting | No | No |
| BYOC | No | No |
| Open source | No | No |
| Scoped API keys | Yes | Not published |
| Spend limits | Yes | Not published |
| Usage per sandbox (API) | Yes | No |
| Audit logs | No | Not published |
| SSO | No | Yes |
| SOC 2 | No | No |
| HIPAA | No | No |
| EU data residency | Yes | No |
| Zero data retention | Yes | Not published |
Performance
There is no comparable measurement for Docker Cloud Sandboxes yet: it launched in September 2026 and is not in the hpc-sandbox-benchmarks runs, and Docker does not say what hardware it uses. boat did 26.69 runs per second on the same Node.js build-and-test benchmark at 4 vCPU / 8 GB, on dedicated AMD Ryzen 9 9950X hosts.
Node.js build-and-test loop at 4 vCPU / 8 GB, higher is better. Measured with the open hpc-sandbox-benchmarks suite. Docker Cloud Sandboxes has no published run in this suite yet, so there is no like-for-like number to compare.
Pricing in five scenarios
Each bill is priced from the providers' public price lists by the open Battleships engine, with the cheapest plan that runs the scenario.
| Scenario | boat, a month | Docker Cloud Sandboxes, a month |
|---|---|---|
| One coding agent, workdays 4 vCPU / 8 GB, 50 GB disk, 8 hours a day, 22 days a month, files kept between days | $20 · $20/mo | $49 · Docker Agentic Platform (pay-as-you-go) |
| One agent that never stops 4 vCPU / 8 GB, 50 GB disk, running 24/7 all month | $26 · $20/mo | $204 · Docker Agentic Platform (pay-as-you-go) · with limits |
| 50 agents in parallel 50 machines of 4 vCPU / 8 GB at once, 8-hour sessions, 1,100 sessions a month, Docker inside | $317 · $20/mo × 3 seats | $2,464 · Docker Agentic Platform (pay-as-you-go) · with limits |
| Sandboxes for your users 2 vCPU / 4 GB, 30,000 sessions of 10 minutes a month, up to 300 at once | $200 · $100/mo × 2 seats | $700 · Docker Agentic Platform (pay-as-you-go) · with limits |
| 1,000 short jobs at once 2 vCPU / 4 GB, 1,000 at once, 3 minutes each, 200,000 jobs a month | $2,000 · $2000/mo · with limits | $1,400 · Docker Agentic Platform (pay-as-you-go) · with limits |
boat: Plans start at $20 a month, and the whole fee is usage credit. You pay per second while a sandbox runs, and a stopped sandbox costs nothing and keeps its disk.
Docker Cloud Sandboxes: Docker bills per second for the size you pick, from $0.07 an hour for 1 vCPU / 2 GiB to $1.12 an hour for 16 vCPU / 32 GiB, with no monthly fee. A stopped sandbox costs nothing, and volumes and egress are free; model calls are billed by your model provider.
Limits in those scenarios
Docker ends every sandbox 24 hours after creation, so one agent that never stops does not fit in a single session. Its default quota of 10 concurrent sandboxes is what rules it out for 50 agents in parallel, for sandboxes for your users and for 1,000 short jobs at once, and Docker publishes no way to raise it. boat has no session cap, but its start limits are lower than a 1,000-job burst needs, so even the $2,000 plan queues those starts.
| Scenario | boat | Docker Cloud Sandboxes |
|---|---|---|
| One coding agent, workdays | None that bite | None that bite |
| One agent that never stops | None that bite |
|
| 50 agents in parallel | None that bite |
|
| Sandboxes for your users | None that bite |
|
| 1,000 short jobs at once |
|
|
Which one should you use?
Use Docker Cloud Sandboxes when
you already run agents in sbx on your laptop and want a few of them to keep going in the cloud for up to a day, with memory kept across stops and strict outbound rules.
- Stop and fork with memory. Useful for agents that pause between steps: a stopped sandbox comes back with its memory and running processes.
- Outbound rules at the proxy. Teams that must limit where an agent connects can set allow and deny rules by host, enforced outside the VM.
- The same sandbox on your laptop. If you already run sbx locally, the cloud is the same microVM and CLI, and you can move work between them.
Use boat when
your agents run for days or by the dozen, need Android emulators, a desktop or a browser, or have to be driven from your own app through an API.
- Runs as long and as wide as the work. An agent on a multi-day task on Docker has to be stopped and resumed by your code before the 24-hour mark, and the eleventh agent waits for a free slot.
- A whole machine, screen included. An agent that has to test a mobile app, click through a web UI or log into a site cannot do it from a terminal, so on Docker you would add a separate browser service.
- Drive agents inside from outside. To run agents from your own app or queue on Docker, you write your own wrapper around terminal input and output, then parse the agent's text to know when it is done.
Questions people ask
Is boat cheaper than Docker Cloud Sandboxes?
For one coding agent on workdays, yes: $20 a month on boat against $49 on Docker for the same 4 vCPU / 8 GiB machine. In the other four scenarios Docker does not fit, because of its 24-hour session cap or its default of 10 sandboxes at once.
Can a Docker cloud sandbox run longer than 24 hours?
Not in one session. A Docker cloud sandbox expires after one hour by default, and extensions cannot go past 24 hours from creation; resuming a stopped one starts a new timer. boat has no session cap on paid plans.
How many Docker cloud sandboxes can I run at once?
The default is 10 concurrent and 50 stored per account, and Docker asks you to confirm your limits with them before planning bigger work. boat's $20 plan runs 100 at once, and higher plans go up to 2,000.
Can I run Docker, Android emulators or a browser in each?
Both run Docker inside the sandbox. boat also exposes /dev/kvm for Android emulators and VMs and has a 60fps desktop with Chromium, while Docker's cloud sandboxes are terminal sessions.
Can boat keep a sandbox's memory when it stops, like Docker?
No. boat saves the disk every minute and when the sandbox stops, so files survive, but resuming boots the machine again. Docker keeps memory and files on stop and can fork a running sandbox with its memory.
Is boat SOC 2 compliant?
SOC 2 is in progress. We're open about where we stand: live status at status.ascii.dev and our data retention policy at docs.boat.dev/data-retention.
Start a sandbox
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