The Vercel Sandbox SDK and CLI now support setting environment variables at sandbox creation that are automatically available to every command.

When running multi-step processes in a Vercel Sandbox like installing dependencies, building a project or starting a dev server, each step often needs the same environment variables. Now, these are available with every runCommand call.

await using sandbox = await Sandbox.create({
  env: { HELLO: "world", DEBUG: "true" },
});
// Prints "world" (inherited from Sandbox.create)
await sandbox.runCommand({ cmd: "node", args: ["-p", "process.env.HELLO"] });
// Prints "false" (overrides the DEBUG value)
await sandbox.runCommand({ cmd: "node", args: ["-p", "process.env.DEBUG"], env: { DEBUG: "false" } });

Environment variables passed to Sandbox.create() are inherited by all commands automatically. Per-command env in runCommand can still override individual values when needed.

Update to the latest Sandbox CLI and SDK, run npm i @vercel/sandbox to get started.