Custom images
Build an image from a package list, a public image or a Dockerfile, and start every sandbox from it.
Volumes
Persistent disks that outlive sandboxes, attached read-write to one or read-only to many.
Previews
Give any port in a sandbox an HTTPS address at runtimehost.com, private with a token unless you make it public.
A desktop in any sandbox
Start a Linux desktop and drive it with clicks, keys and screenshots, or watch it live.
Code interpreter
A notebook-style Python or JavaScript session in a sandbox, with charts returned as images.
Network rules per sandbox
Allow or deny hosts, turn the internet off, and open host:port pairs such as a database on a paid account.
Interactive terminals
runtime sandbox shell opens a real terminal in a sandbox, and the API serves one over WebSocket.
Read-only keys and daily spending limits
An owner can give an agent a key that changes nothing, or cap what it may spend in any 24 hours.
Buy credit by card
Add any amount from $10 to $10,000, with no subscription.
Referrals
Refer a company and you both get credit equal to its first top-up, up to $500 each.
A 20-hour free trial
Every new account gets 20 sandbox hours (now 100) with no card.
One line connects your agent
claude mcp add --scope user runtime -- npx -y withruntime mcp (or the same for Codex and Cursor) is the whole setup; the agent asks for one browser approval.
runtime run
One command creates a sandbox, runs your command, prints its output and stops it, connecting the machine on first use.
In the official MCP registry
Runtime Cloud is listed for any MCP client to find.
The withruntime package
Both SDKs publish as withruntime on npm and PyPI, and the old names still install it.
API 0.2.0
One API for every product, over HTTP/2, with a public OpenAPI document.
A hundred commands at once
One key can have 128 requests in flight, so an agent can fan out without refusals.
Idle sandboxes pause themselves
A sandbox left on the default lease and never used pauses after five minutes (now any sandbox after a minute with nothing happening in it), so it stops paying the running rate.
Ask support anywhere
Ask from the dashboard, with runtime support, or at support@withruntime.com.