CodeSandbox SDK

CodeSandbox SDK — Firecracker VMs with memory snapshots, from the online IDE, now owned by Together AI. CodeSandbox spent years making browser-based development environments resume instantly, and the SDK sells that infrastructure directly: microVMs that hibernate to a memory snapshot, resume with processes intact, and fork cheaply from any snapshot. Together AI acquired the company in 2025. The snapshot-and-fork model is the most mature in this roster, and pricing is credit-based rather than hourly. Built by Together AI. Founded 2017. Acquired.

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.

• Snapshot & fork — Yes, which only 5 of 18 tools here manage.
• Funding — acquired, 5th of 15.

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.

• Egress control — open, 13th of 16. Daytona records allowlist.
• MCP server — No. Daytona records Yes.

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. 25 of 26 tracked fields carry a value for CodeSandbox SDK, and 7 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. CodeSandbox SDK is ahead on Meter (per-second against subscription) and Snapshot & fork (Yes against Partial). That pattern repeats across the rest of the roster — see CodeSandbox SDK alternatives for the other rivals, each compared the same way.

Company

Together AI

Founded

2017

Funding

Acquired

Fields we track

25 of 26

Last verified

2026-01-15

If your workload branches — try five patches from one prepared state — this is the best-engineered snapshot implementation available, because CodeSandbox spent years being punished for slow resumes. The open question is roadmap: it is now a component of Together AI's stack rather than a company's whole product.

Cold start

1.2 s10th of 16

Inferred

Snapshot & fork

●Yes1st of 18

Vendor-claimedverified 2026-01-15source

Egress control

open13th of 16

Inferred

MCP server

○No12th of 16

Inferred

Isolation

microvm1st of 16

Vendor-claimedverified 2026-01-15source

Custom images

●Yes1st of 20

Inferred

Streaming output

●Yes1st of 16

Vendor-claimedverified 2026-01-15source

Max runtime

1440 min1st of 16

Inferred

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

• You fork one prepared environment many times.
• Long-lived per-user environments that hibernate between sessions.
• You need processes and memory preserved, not just the disk.
• Snapshot & fork is your binding constraint. CodeSandbox SDK records Yes, which only 5 of the 18 tools in the Sandbox providers roster do. We define that field as whether you can freeze a running sandbox and restore or clone it.
• Funding is your binding constraint. CodeSandbox SDK records acquired, 5th of 15 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:

• Egress control. CodeSandbox SDK records open, 13th of 16 in the Sandbox providers roster. Daytona records allowlist on the same field. If that is a hard requirement rather than a preference, start elsewhere.
• MCP server. CodeSandbox SDK 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.

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. 1 of the 26 fields we track for CodeSandbox SDK are still blank: Price / hour. 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.