Sandboxes for AI agents
A safe place for your agents to run code.
Every agent run gets its own small virtual machine. Create it from an API, a CLI or an MCP server. When the run is over, keep the disk or throw it away.
What you get
Three things we work hard to get right
Your work is saved
While a sandbox runs, we snapshot its disk every minute if something changed. When you stop it, we take one more. Snapshots are stored off the host, so a dead machine does not take your work with it.
- Resume a stopped sandbox from its disk.
- Save a snapshot by name and start new sandboxes from it.
A stop keeps the disk, not running processes. If a host goes silent for five minutes, we restart its sandboxes on another host from their last snapshot. You can lose up to about a minute of disk changes and any running processes.
Your keys stay out
With the credential proxy on, an API key for an HTTPS service never enters the VM. The sandbox holds a placeholder. We swap in the real key on the host, only for that service.
- You can list the domains a sandbox may reach.
- A "no env" sandbox gets nothing from your account.
On for new accounts, free on every plan. Accounts that already exist keep the setting they had.
Your bill is easy to follow
Every sandbox has a lease, one hour by default. It stops when the lease ends and keeps its disk, unless you renew it or turn on never auto-stop. The sandbox list shows what each one has cost you this month.
- The list and the meter use the same records.
You can set a monthly spend cap for each member. Caps for a single sandbox or the whole organization are not built yet. See pricing.
How it works
Create it, use it, fork it, throw it away
Drive runner from the CLI, the HTTP API or any MCP client. Every error has a code you can branch on and a fix.
A sandbox starts from its saved disk. In a design test, laying a disk of 100,000 files back down inside a VM took 1.14 to 1.94 seconds. That leaves out the download from storage, so it is not a promise about how long a start takes.
CLI · MCP server · HTTP API
# a sandbox that can reach pypi.org and nothing else runner new \ -ttl-seconds 7200 \ -allow-domain pypi.org # branch it, disk included, to try a risky step runner fork sbx_123
Who it is for
Teams whose agents run for paying customers
Coding agents, computer-use agents, tools behind an MCP server and CI jobs. If a lost run, a leaked key or a surprise bill costs you more than the machine time, runner is for you.
Who it is not for
What we do not do
- GPU workloads
- Windows, macOS or Android guests
- Jobs that need KVM inside the guest
- Bursts of 10,000 or more sandboxes at once
We do not ship Python or TypeScript SDKs yet. Use the CLI, the HTTP API or the MCP server.
Want to try it?
Public signup is not open yet. Ask for early access and we will write back when your account is ready.