Runtime vs Vercel Sandbox

Runtime and Vercel Sandbox both use Firecracker microVMs and bill active CPU; Runtime charges less, and a pause keeps memory.

This page compares the two for teams looking for a Vercel Sandbox alternative. Facts about Vercel come from its public pricing and documentation, checked 22 September 2026, at the rates of its default iad1 region; check the links at the end before relying on them. Equal vCPU counts do not prove equal performance, and the two services have not been benchmarked against each other.

At a glance

Cost for the same job

Take 1,000 runs of a 2 vCPU sandbox with 4 GiB on Runtime and 4 GB on Vercel. Each run lasts 60 seconds and keeps the CPU busy for 20 CPU-seconds, which is typical of an agent that spends most of its time waiting for a model.

TextRuntime  CPU    1,000 × 20 s / 3,600 × $0.025      = $0.14         Memory 1,000 × 60 s / 3,600 × 4 × $0.0075 = $0.50         Total                                        $0.64Vercel   CPU    1,000 × 20 s / 3,600 × $0.128      = $0.71         Memory 1,000 × 60 s / 3,600 × 4 × $0.0212 = $1.41         Total                                        $2.12

Both bill CPU by use, so the gap holds as a workload gets busier: with both CPUs busy for the whole minute, the same job costs $1.33 on Runtime and $5.68 on Vercel. A GiB is about 7% larger than a GB, so Runtime's memory figure covers slightly more. Creations, network, storage, plan fees, taxes and free allowances are excluded from both. See pricing for Runtime's terms.

Where Vercel Sandbox is stronger

• Regions and scale. Vercel runs sandboxes in 19 regions, with up to 10,000 at once on Pro. Runtime runs in one region.
• Size. Enterprise sandboxes go up to 32 vCPUs and 64 GB.
• Persistence. Vercel sandboxes save their filesystem on every stop by default, and Drives add persistent storage that sandboxes can share.
• Platform. If your application already runs on Vercel, sandboxes share its account, billing and observability, and Vercel reports SOC 2 Type II. Runtime has not completed an outside security audit.
• Snapshots. Runtime's are paused while an issue is fixed; build a custom image to start many sandboxes from one setup.

Where Runtime is stronger

• Price. Active CPU costs about a fifth as much, and memory about a third.
• Memory survives a pause. A paused Runtime sandbox wakes with its processes still running. See pricing for paused storage.
• Setup by the agent. An agent runs npx withruntime run --trial -- ..., shows you a link, and starts work once you approve it in the browser. No API key is copied into a prompt or a config file, and the MCP server reuses the same connection.
• No platform to join. Runtime needs no hosting plan or project; prepaid credit is the whole account.

Moving from Vercel Sandbox

Vercel Sandbox:

JavaScriptimport { Sandbox } from "@vercel/sandbox";const sandbox = await Sandbox.create();const command = await sandbox.runCommand("echo", ["hello"]);console.log(await command.stdout());await sandbox.stop();

Runtime:

TypeScriptimport { Sandbox } from "withruntime";const box = await Sandbox.create({ funding: "trial" });try {  console.log((await box.exec("echo hello", { check: true })).stdout);} finally {  await box.stop();}

To have a coding agent make the switch, test it and compare costs on your own workload, give it the prompt in migration. Keep Vercel Sandbox available until the same job passes on both.

Sources

• Vercel Sandbox pricing and quotas
• Understanding Vercel Sandboxes
• Runtime pricing, security and products