Vercel Sandbox

Vercel Sandbox — Firecracker microVMs for running untrusted code from inside a Vercel deployment. Vercel Sandbox runs Firecracker microVMs on the same infrastructure as Vercel Functions, exposed through an SDK meant to be called from a Vercel app. The product has moved a long way from its ephemeral launch: sandboxes are now persistent by default, snapshotting their filesystem on stop and resuming from it, with an explicit fork call, custom images from Vercel's container registry, and a per-sandbox egress firewall that takes a domain allowlist. Billing follows Vercel's active-CPU model, which is unusually kind to agent workloads that spend most of their life waiting. The catch is placement: it runs in a single US region. Built by Vercel. Founded 2015. Series F.

We track it in 1 comparison — Sandbox providers — so every claim below is a cell in a table you can open and check rather than an impression. Across those rosters it sits against 19 other tools, and what follows is where it visibly separates from them.

Where it wins.

• Concurrent limit — 2,000 sandboxes, tied for best across 2 of 13 tools.
• Funding — series-c-plus, tied for best across 4 of 15 tools.

Each of those is ranked against the whole roster on its category page, not against a hand-picked subset, so a first place here means first of everything we list.

Where it gives ground.

• MCP server — No. Daytona records Yes.
• Browser inside — No. E2B records Yes.
• SDKs — typescript, 14th of 16. Runloop records python, typescript, rest-api, cli.
• Price / hour — $0.341 /hr, the weakest of the 9 here. Self-hosted Firecracker records $0.03 /hr.

None of these disqualify it on their own. They are the fields to check against your own requirements before you commit, because they are the ones where a competitor genuinely does better.

Provenance. 24 of 26 tracked fields carry a value for Vercel Sandbox, and 16 of those cite a document you can open. Last verified 2026-07-23. Every figure keeps its own provenance — measured by us, claimed by the vendor, inferred, or community-reported — and we would rather print a dash than a guess.

Its nearest neighbour in our data is ascii. Vercel Sandbox is ahead on Meter (per-second against subscription) and Custom images (Yes against Partial). That pattern repeats across the rest of the roster — see Vercel Sandbox alternatives for the other rivals, each compared the same way.

Company

Vercel

Founded

2015

Funding

Series F

Fields we track

24 of 26

Last verified

2026-07-23

No longer the deliberately narrow product it launched as, and this row was wrong about it for months. Persistence is now the default, snapshots and fork are shipped and billed, custom images come from Vercel's own registry, sessions run 24 h on a paid plan, and the egress firewall — deny-all or a per-sandbox domain allowlist, updatable while the sandbox runs — is one of the better isolation stories here rather than an omission. What remains genuinely narrow is placement: iad1 and nothing else, which rules it out for data residency and adds a fixed round trip from anywhere that is not the US east coast. The active-CPU meter is still the quiet advantage, because an agent session blocked on inference costs a fraction of the headline rate.

Cold start

1.8 s13th of 16

Inferred

MCP server

○No12th of 16

Inferred

Concurrent limit

2,000 sandboxes1st of 13

Vendor-claimedverified 2026-07-23source

Browser inside

○No13th of 16

Inferred

Funding

series-c-plus1st of 15

Community-reported

SDKs

typescript14th of 16

Inferred

Isolation

microvm1st of 16

Vendor-claimedverified 2026-07-23source

Price / hour

$0.341 /hr9th of 9

Inferredverified 2026-07-23source

Vercel Sandbox is the right call in these situations, each one drawn from a field we actually record:

• An app-builder or code-runner inside a Vercel deployment.
• Agent sessions that mostly wait on a model, where active-CPU billing pays off.
• You need a per-sandbox egress allowlist without building it yourself.
• Concurrent limit is your binding constraint. Vercel Sandbox records 2,000 sandboxes, the best figure in the Sandbox providers roster. We define that field as concurrent sandboxes allowed on the standard paid tier without contacting sales.
• Funding is your binding constraint. Vercel Sandbox records series-c-plus, the best figure in the Sandbox providers roster. We define that field as latest disclosed funding stage of the company operating the product, as a crude proxy for how long it can keep subsidising compute.

Reach for something else when any of the following is a requirement rather than a nice-to-have:

• MCP server. Vercel Sandbox records No on the Sandbox providers table. Daytona records Yes on the same field. If that is a hard requirement rather than a preference, start elsewhere.
• Browser inside. Vercel Sandbox records No on the Sandbox providers table. E2B records Yes on the same field. If that is a hard requirement rather than a preference, start elsewhere.
• SDKs. Vercel Sandbox records typescript, 14th of 16 in the Sandbox providers roster. Runloop records python, typescript, rest-api, cli on the same field. If that is a hard requirement rather than a preference, start elsewhere.
• Price / hour. Vercel Sandbox records $0.341 /hr, the weakest of the 9 tools in the Sandbox providers roster. Self-hosted Firecracker records $0.03 /hr on the same field. If that is a hard requirement rather than a preference, start elsewhere.

We publish this block because a comparison that only lists what a tool is good at is marketing. Every figure above sits on the same page as its source, and the field definitions are on the category tables if you want to check how we measured them.

What we don't know. 2 of the 26 fields we track for Vercel Sandbox are still blank: Cold start (claimed) and GitHub stars. Those render as dashes rather than as zeroes or assumptions, because an empty cell and a bad cell are not the same thing and only one of them is honest. If you know any of these figures and can point at a document, tell us.