Expose SSH

Sandboxes can hand out SSH credentials so you can inspect the filesystem, tail logs, run editors, or forward ports while the microVM stays isolated on the Deploy edge.

import { Sandbox } from "@deno/sandbox";

await using sandbox = await Sandbox.create();

const { hostname, username, privateKey } = await sandbox.exposeSsh();
console.log(`ssh ${username}@${hostname}`);

// keep process alive or interact via SSH until done...
await new Promise((resolve) => setTimeout(resolve, 10 * 60 * 1000));

The sandbox remains reachable for the configured lifetime. Once your script releases its references (for example, the await using block ends) the sandbox shuts down and the SSH endpoint disappears; you can also call sandbox.kill() if you need to tear it down immediately.

When to use SSH access Jump to heading#

• Debugging agent-generated code that only fails in the sandbox
• Editing files with a full-screen terminal editor or remote VS Code
• Streaming logs in real time without instrumenting application code
• Running profiling or inspection tools that are easier to use manually

Because each sandbox is already isolated, opening SSH does not compromise other projects or organizations.

Connecting from your machine Jump to heading#

1. Request credentials via sandbox.exposeSsh().
2. Store the returned privateKey (or identityFile) to a temporary file with chmod 600 permissions.
3. Connect using the provided username and hostname:

ssh -i ./sandbox-key ${username}@${hostname}

4. Use regular terminal workflows: copy files, run top, tail logs, or attach to running processes.

Security considerations Jump to heading#

• Credentials are single-use and bound to the sandbox lifetime.
• You control how long the sandbox runs; destroy it to revoke access instantly.

Keeping the sandbox alive Jump to heading#

The SSH tunnel closes if the sandbox shuts down. Keep it running by:

• Setting lifetime: "session" (default) and keeping your managing script active
• Passing lifetime: "5m" (or another duration) when creating the sandbox so it persists after the script exits, then reconnecting later with Sandbox.connect({ id })

Cleanup is automatic when your code stops referencing the sandbox, but you can run sandbox.kill() (or simply exit inside the SSH session) if you want to end it on demand.

Example workflow Jump to heading#

import { Sandbox } from "@deno/sandbox";
import { writeTextFile } from "node:fs/promises";

await using sandbox = await Sandbox.create({ lifetime: "10m" });

// Prepare the app
await sandbox.upload("./app", ".");
await sandbox.sh`deno task dev`
  .noThrow(); // start server; leave running for inspection

// Get SSH details and write key to disk
const ssh = await sandbox.exposeSsh();
await writeTextFile("./sandbox-key", ssh.privateKey);
await sandbox.sh`chmod 600 sandbox-key`;

console.log(`Connect with: ssh -i sandbox-key ${ssh.username}@${ssh.hostname}`);

// Block until you're done debugging manually
await new Promise((resolve) => setTimeout(resolve, 10 * 60 * 1000));

Use this pattern to investigate flaky builds, run interactive REPLs, or pair with teammates without promoting the code to a full Deploy app.