Freestyle

Freestyle — Run untrusted JavaScript and full dev servers, with git hosting and domains built in. Freestyle targets the specific shape of app-builder products: execute untrusted JavaScript, run a dev server the user can see, host the git repository, and attach a domain. That vertical integration is the point — the sandbox, the repo and the preview URL are one product rather than three vendors. The tradeoff is a JavaScript-centric runtime story and a much smaller surface than general-purpose providers. Founded 2024. Seed.

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 gives ground.

• Custom images — No. E2B records Yes.
• Max runtime — 60 min, 13th of 16. E2B records 1440 min.
• Browser inside — No. E2B records Yes.
• Funding — seed, 9th of 15. Fly.io Machines records series-c-plus.

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. 22 of 26 tracked fields carry a value for Freestyle, and 1 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. Freestyle is ahead on Meter (per-request against subscription) and Preview URLs (Yes against Partial). ascii takes Custom images (Partial against No) and Root in guest (Yes against Partial). That pattern repeats across the rest of the roster — see Freestyle alternatives for the other rivals, each compared the same way.

Founded

2024

Funding

Seed

Fields we track

22 of 26

Last verified

2026-01-15

Not a general sandbox and not pretending to be. If you are building a Lovable-shaped product, Freestyle collapses four vendors into one and the preview-and-domain plumbing alone justifies it. For anything outside JavaScript app-building it is the wrong shape.

Cold start

700 ms7th of 16

Inferred

Custom images

○No18th of 20

Inferred

Max runtime

60 min13th of 16

Inferred

Browser inside

○No13th of 16

Inferred

Isolation

microvm1st of 16

Inferred

Egress control

allowlist1st of 16

Inferred

Streaming output

●Yes1st of 16

Inferred

Persistent FS

●Yes1st of 16

Inferred

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

• Building an AI app builder with live previews.
• You want git hosting and custom domains bundled with execution.
• JavaScript and TypeScript workloads only.

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

• Custom images. Freestyle 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.
• Max runtime. Freestyle 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.
• Browser inside. Freestyle 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.
• Funding. Freestyle records seed, 9th of 15 in the Sandbox providers roster. Fly.io Machines records series-c-plus 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. 4 of the 26 fields we track for Freestyle are still blank: Cold start (claimed), Concurrent limit, Price / hour 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.