Cloudflare Sandbox

Cloudflare Sandbox — Container sandboxes driven from a Worker, addressed through Durable Objects. Cloudflare's Sandbox SDK runs containers on Cloudflare Containers and gives each one a Durable Object as its control plane, so a sandbox becomes addressable, stateful and callable directly from Worker code. Billing is metered in 10 ms increments and stops when the container sleeps. It is the lowest-friction option if your app already lives on Workers, and largely irrelevant if it does not. Built by Cloudflare. Founded 2009. Public. Open source under MIT.

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.

• Idle cost — free-when-stopped, tied for best across 5 of 16 tools.
• Meter — per-10ms, the best figure of the 19 here.
• Funding — public, 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.

• Snapshot & fork — No. Daytona records Yes.
• Isolation — container, 14th of 16. E2B records microvm.
• Persistent FS — No. Modal records Yes.
• Max runtime — 60 min, 13th of 16. E2B records 1440 min.

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 Cloudflare Sandbox, and 9 of those cite a document you can open. Last verified 2026-01-15. 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. Cloudflare Sandbox is ahead on Meter (per-10ms against subscription) and Custom images (Yes against Partial). ascii takes Snapshot & fork (Partial against No). That pattern repeats across the rest of the roster — see Cloudflare Sandbox alternatives for the other rivals, each compared the same way.

Company

Cloudflare

Founded

2009

Funding

Public

Licence

MIT (open source)

Fields we track

24 of 26

Last verified

2026-01-15

Structurally the most interesting design here — a sandbox that is an addressable object in your app, with egress you gate in Worker code — and the slowest to cold start. Take it if your stack is already Workers; do not migrate to Cloudflare for the sandbox alone.

Snapshot & fork

○No15th of 18

Inferred

Cold start

3 s14th of 16

Inferred

Isolation

container14th of 16

Vendor-claimedverified 2026-01-15source

Idle cost

free-when-stopped1st of 16

Vendor-claimedverified 2026-01-15source

Persistent FS

○No14th of 16

Inferred

Max runtime

60 min13th of 16

Inferred

Meter

per-10ms1st of 19

Vendor-claimedverified 2026-01-15source

Price / hour

$0.18 /hr6th of 9

Inferred

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

• Your app already runs on Workers and Durable Objects.
• You want code-level control over what the sandbox can reach.
• Sandboxes are long-lived per user rather than created in bursts.
• Idle cost is your binding constraint. Cloudflare Sandbox records free-when-stopped, the best figure in the Sandbox providers roster. We define that field as what you pay while a sandbox exists but is doing nothing — the common case when an agent is blocked on model inference.
• Meter is your binding constraint. Cloudflare Sandbox records per-10ms, the best figure in the Sandbox providers roster. We define that field as the smallest unit the meter rounds to.
• Funding is your binding constraint. Cloudflare Sandbox records public, the best figure in the Sandbox providers roster.

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

• Snapshot & fork. Cloudflare 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.
• Isolation. Cloudflare Sandbox records container, 14th of 16 in the Sandbox providers roster. E2B records microvm on the same field. If that is a hard requirement rather than a preference, start elsewhere.
• Persistent FS. Cloudflare Sandbox records No on the Sandbox providers table. Modal records Yes on the same field. If that is a hard requirement rather than a preference, start elsewhere.
• Max runtime. Cloudflare Sandbox records 60 min, 13th of 16 in the Sandbox providers roster. E2B records 1440 min on the same field. If that is a hard requirement rather than a preference, start elsewhere.
• SDKs. Cloudflare 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.

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 Cloudflare 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.