Runtime for ComputeSDK

Create Runtime sandboxes through ComputeSDK's provider interface, with commands, streaming, files, preview URLs and snapshots.

@computesdk/runtime is a ComputeSDK provider, like its E2B, Modal or Daytona providers. Change the provider and the same compute.sandbox code runs in a Firecracker microVM with its own kernel. It is built on Runtime's TypeScript SDK, withruntime.

Install

ComputeSDK publishes its providers to npm itself, from its own repository. The Runtime provider is written for that repository; this command works once ComputeSDK has merged and published it:

Terminalnpm install computesdk @computesdk/runtime

It needs Node.js 22 or later. The key comes from RUNTIME_API_KEY or this machine's npx withruntime login, as for the rest of the SDK.

Example

JavaScriptimport { runtime } from "@computesdk/runtime";const compute = runtime({ apiKey: process.env.RUNTIME_API_KEY });const sandbox = await compute.sandbox.create({ envs: { NODE_ENV: "production" } });try {  const result = await sandbox.runCommand("node --version");  console.log(result.stdout);  await sandbox.runCommand("python3 -m http.server 3000", { background: true });  console.log(await sandbox.getUrl({ port: 3000 }));} finally {  await sandbox.destroy();}

sandbox.getInstance() returns the withruntime sandbox, for everything ComputeSDK's interface does not cover: processes, terminals, network rules, the desktop and the rest.

Options

Every option is optional.

Option	What it does
`apiKey`	The API key; defaults to `RUNTIME_API_KEY`, then the key `npx withruntime login` saved
`baseUrl`	The API origin; defaults to `RUNTIME_API_URL`, then `https://api.withruntime.com`
`create`	Defaults for every create: `funding`, `region`, `image`, `vcpu`, memory, disk, `network` and any other field
`previewVisibility`	`private` (default): the URL from `getUrl` carries its token; `public`: anyone with the address
`previewTtlSeconds`	How long a private preview's token lasts, 60 seconds to 7 days; one day by default

compute.sandbox.create() takes ComputeSDK's own options and maps them: templateId is a Runtime image, snapshotId a Runtime snapshot, metadata becomes labels, timeout the lease, vcpus, memoryMiB and diskMiB the size, and envs is set on every command the provider runs in that sandbox.

How ComputeSDK's calls behave

Commands run under bash -c, for 60 seconds unless timeout says otherwise (up to 24 hours). One that runs past its timeout returns exit code 124 with its output so far. background: true starts a Runtime process and returns at once.
Streaming. onStdout and onStderr receive output through Runtime's API as the command writes it, so ComputeSDK needs no port inside the sandbox.
Files use Runtime's file calls, not shell commands.
getUrl shares the port as a private preview and returns a link that carries its token. A browser keeps the token as a cookie; a client that does not keep cookies, such as fetch, sends the token from getInstance().previews.get(port) as the x-runtime-preview-token header.
destroy stops the sandbox. getById returns null for a stopped one, and a paused one wakes when used.
Snapshots keep files, memory and running processes; create, list and delete work, and snapshotId starts a sandbox from one.
envs from create are held by the provider object that created the sandbox. A sandbox reached through getById or list does not have them; pass env to runCommand there.

What was verified

On 25 September 2026 the provider was built in a clone of ComputeSDK's repository (commit d52afb5) against withruntime 0.5.1 from npm. There its CommonJS and ESM builds, type declarations, typecheck and lint passed; 28 unit tests passed with the Runtime SDK mocked; ComputeSDK's shared provider suite passed against ComputeSDK's own mock sandbox; and both builds loaded withruntime and called a local stand-in for Runtime's API.

It has not yet run against Runtime itself. ComputeSDK's shared suite and the create, reconnect, list and destroy test run live with RUNTIME_API_KEY set; they have not run yet.