Linux boxes on boat.dev

boat.dev rents Linux virtual machines, which it calls sandboxes, by the second. With a boat.dev backend, each box is a sandbox of its own that BB Box makes when a thread asks for one, and deletes when the box is released. You need no server of your own. Why it works this way is in decision 068.

This page sets it up from a new boat.dev account. It was first done on 29 October 2026.

What it costs

boat.dev bills a sandbox for every second it runs. A stopped sandbox costs nothing for 14 days. boat.dev’s prices on 29 October 2026:

A box of	An hour
2 vCPU, 4 GB, 51 GB disk (`small`)	$0.018
4 vCPU, 8 GB, 51 GB disk (`default`)	$0.036
8 vCPU, 16 GB, 111 GB disk (`large`)	$0.072
16 vCPU, 32 GB, 251 GB disk (`xlarge`, on the $100 plan or higher)	$0.20

A plan’s price comes back as sandbox time at these prices, and boat.dev uses it first. BB Box gives each box the smallest size that has at least the cores, memory and disk the box asks for, so a box can have more than it asked for.

BB Box also keeps a stopped template sandbox for each kind, which every box of the kind is a copy of. A stopped sandbox costs nothing. Building one takes a sandbox of the default size for about 6 minutes for Linux and 13 for a Linux desktop, one template at a time, when the first box of the kind needs it and again after a week or when the scripts its build runs change. If BB Box restarts during a build, as it does on an update, the new BB Box carries on with that build in the same sandbox rather than start another. A template sandbox is named bb-box linux template, building until its scripts end, bb-box linux template, checking while a copy of it is checked, and bb-box linux template once the check passes. Boxes are only made from templates with that last name.

What your plan allows

The free trial lasts 7 days and has 25 hours of compute, in which an hour of a small sandbox counts as half. It allows 2 sandboxes at once, the small and default sizes only, 5 starts a minute and 25 an hour, and auto-stops of at most 2 hours.
A paid plan allows 100 sandboxes at once or more, and more starts.

BB Box also has its own limit, Most boxes, which is 2 by default, a template being built included. When either is reached, a thread that asks for another box is told why.

Before you start

You need:

a boat.dev account, made at boat.dev
a way for the sandboxes to reach your BB server: if BB is on a Tailscale tailnet, set BB Box up to join them to it; otherwise BB’s server needs a URL they can reach. Without either, boxes work, but cannot become BB machines

Set it up

1. Make an API key

In boat.dev’s dashboard, make an API key, or with boat.dev’s command line:

boat api-key create bb-box

The key starts with boat_. A key that expires stops working for BB Box when it does, so give it a long life, or none.

2. Add the backend to BB Box

In BB Box’s settings, find boat.dev under Backends and select Set up.
Paste the key into API key.
Set Most boxes to how many boxes you are willing to pay for at once.
Select Save, and turn the backend on.

The key is kept as a secret. BB Box’s settings show only that it is set.

3. Turn on the kinds

Under Kinds, turn on Linux and Linux desktop, if you want them from boat.dev, and Android emulator for Android boxes.

Check it works

bb box doctor

The doctor checks that boat.dev accepts the key and says what your plan allows now: sandboxes at once, starts left, the sizes and their prices, and on the trial the compute hours left. It says when each template was built, and lists the sandboxes BB Box has.

Then make a box from the Box panel, or ask an agent to. The first box of each kind waits for its template, and says so while it waits.

What a box is like

A box is a virtual machine of its own: Ubuntu 24.04, with its own kernel, systemd, Docker and KVM, and BB Box’s tools, as on its other backends. You use it as box, who can use sudo. A desktop box has the same desktop and apps as a Linux desktop on BB Box’s other backends, drawn by the CPU, with computer use, and you watch and use it in the Box panel. Once its template is built, a Linux box is ready in 9 to 25 seconds, and a desktop in about 1 to 2 minutes: BB Box copies the template, the copy starts, and boat.dev brings in the template’s system files and starts Docker, and for a desktop its desktop. A desktop then waits until boat.dev has brought in all of the template’s files, about a minute after it starts, before BB Box checks Cua Driver, which stops answering if it is used before then. On a busy boat.dev machine a desktop has taken over 6 minutes.

BB Box reaches each box over SSH, with a key of its own and the host key boat.dev gives, which BB Box checks. A box gets no secret from your boat.dev account.

A box can run VMs and emulators of its own, as boat.dev’s machines have KVM. As boxes cost by the second, a thread that asks for plain linux gets one from boat.dev only when no other backend has room, and one that asks for linux-kvm or linux-vm can get one at once.

Stop, start and the auto-stop

Stopping a box stops its sandbox: its processes end, its disk is kept, and it costs nothing. Starting it again takes a second or two, on a new machine, whose address can differ.

boat.dev stops a sandbox by itself at its auto-stop. BB Box sets each box’s auto-stop to Auto-stop (minutes), 30 by default, and sets it again every few minutes while it holds the box. So a box runs while BB Box holds it, and if BB Box stops for good, its boxes stop within that time and cost nothing more. When BB Box comes back, it finds them stopped, and says why.

Resizing

A box can move to another of boat.dev’s sizes, with a restart: BB Box stops its sandbox and boat.dev starts it again on a machine of the new size, as resizing a box describes. Cores, memory and disk change together, and a smaller size is refused when the box’s files would not fit its disk.

Snapshots

On a paid plan, a snapshot of a box is one of boat.dev’s saved snapshots, as snapshots describes. It holds the box’s disk, not its memory, and leaves out what boat.dev’s own snapshots leave out: /tmp, ~/.cache, the build cache, the hostname, the address and the SSH host keys. A snapshot of a running box takes a fresh capture first, which can take a minute or more.

A saved snapshot lives on your boat.dev account, not on the box, and does not expire by itself. It costs money only past what your plan includes: 10 for every $20 of plan, then $0.056 a day each, from the wallet. The count is the account’s, saved snapshots BB Box did not take included. Each snapshot’s row says the price, and Settings, Snapshots, Paid snapshots says how many of the included ones the account holds. Your ceiling there, $5 a month unless you set it, refuses a snapshot that would bring what boat.dev bills for them past it. Where BB Box cannot read boat.dev’s count just then, it takes, restores with an undo and keeps no saved snapshot until it can, and Settings show an estimate at full price.

A restore stops the box, so boat.dev saves its disk, saves that as the undo, and then makes the box a new sandbox from the snapshot, with the same box ID, name and labels, and deletes the old sandbox. boat.dev counts 2 starts for this, as it gives a sandbox deployed from a saved snapshot no labels, so BB Box deploys it, stops it and copies it with the box’s labels. They are free within your plan’s starts, and from $0.03 each past them, which the restore dialog says before you restore. A restore needs 3 starts left, as putting the box back if the new sandbox fails takes a third. The old sandbox stays, stopped, until the new one has started. A release deletes the box’s saved snapshots with it, unless you kept one.

A snapshot of a Linux server box forks when it was taken with version 8 or later of the identity reset working, which boxes have from a Linux template built with it, once general.identityResetBackends names boat.dev’s backend. The fork is a new sandbox made from the saved snapshot, with the fork’s own identity value, and costs 2 of boat.dev’s starts. Keep holds a saved snapshot past the box’s release as it is, at boat.dev’s daily price past the plan’s included ones, until its keep date. Linux desktops need a template built with reset version 9 or later. Older images refuse forks and Keep, saying why: rebuild the template and make the box again. Android boxes have no identity reset on boat.dev yet, so their snapshots neither fork nor are kept.

A copy of a box’s sandbox made outside BB Box, in boat.dev’s dashboard or with its API, keeps its source’s identity: it comes up as the same BB machine, with the same tailnet node and the thread’s access. Copy a box’s sandbox only through BB Box.

The free trial has no saved snapshots, so a box on it has no snapshots, restores, forks or Keep.

Android boxes

boat.dev’s machines have KVM, so they can run the Android emulator. An Android box on boat.dev is the same as on Proxmox QEMU: a phone, foldable or tablet, booted from its snapshot, with its screen in the Box panel. Using it is in device boxes.

Read the Android SDK’s licence: Google’s terms for the SDK, the emulator and the system image, as setup/android/pins.json pins them. setup/android/accept-sdk-licence.sh shows them, without accepting anything unless you say so.
In BB Box’s settings, under boat.dev, turn on Android SDK licence. That is your acceptance. While it is off, boat.dev offers no Android boxes, and box_list and the doctor say why.
Turn on the Android emulator kind.

BB Box then builds boat.dev’s Android template at its next upkeep, about 30 minutes, as no box can ask for a kind that is not offered yet. Android boxes come once it is ready.

The Android kind’s own sizes start at 8 cores and 16 GB, boat.dev’s large, which the free trial does not allow. Each device also has a least size, from what its emulator holds when busy:

Device	Least size
Pixel 8	4 cores, 8 GiB
Pixel Fold	4 cores, 10 GiB
Pixel Tablet	4 cores, 10 GiB

So on the trial, whose largest size is boat.dev’s default, 4 cores and 8 GB, boat.dev offers the Pixel 8 only: ask for 4 cores and 8 GiB. An Android box is ready once boat.dev has brought in all of the template’s files, about 4 minutes after it starts, and its device boots after that. On the trial’s 4 cores the device draws about 9 to 14 frames a second in the Box panel, and a tap shows in about 150 ms, slower while boat.dev saves the box’s disk, which it does each minute. The Pixel Fold and Pixel Tablet need a paid plan. The doctor’s Android check says the largest size your plan allows, and which devices it leaves out.

Check that nothing is left running

BB Box labels every sandbox it makes with bbbox-install, and its boxes with bbbox-box. To list them with boat.dev’s command line:

boat list --all

Each one should be a box in BB Box’s Boxes page, or a template, with the label bbbox-role=template, stopped. BB Box’s saved snapshots are named after the install, the box and the snapshot, such as abcdefghij-bx...-sn...; boat snapshots lists them, and each should be a snapshot on the Boxes page’s Snapshots tab. BB Box checks its backends every few minutes, and deletes a box’s sandbox once BB says the box’s thread has ended. It deletes an old template an hour after a new one replaces it. bb box doctor lists any sandbox no box claims. If one stays, delete it with boat delete followed by its ID.

Turn it off

Release the boxes on boat.dev.
Delete the saved snapshots BB Box took, kept ones included: bb box snapshot list --all names them, and bb box snapshot delete deletes each one. A saved snapshot outlives its box and goes on costing past the plan’s included ones, so BB Box refuses to remove the backend while boat.dev holds any of this install’s, and names them; delete any it has no record of in boat.dev’s dashboard.
Turn the boat.dev backend off in BB Box’s settings. Boxes it already has keep working until they are released.
Delete the templates with boat delete, and check that boat list --all lists nothing of BB Box’s.
Revoke the key in boat.dev’s dashboard.