AI code-execution sandbox
CodeSandbox SDK
CodeSandbox SDK (now Together Code Sandbox) runs Firecracker microVMs with a git-versioned filesystem, ~500ms resume and sub-second forking, tuned for web-dev agents.
Last verified 2026-07-26
CodeSandbox SDK — rebranding as Together Code Sandbox under Together AI — offers Firecracker microVMs with a git-versioned filesystem, ~500ms resume, sub-second forking and a 2.7s P95 cold start. It is focused on web-development agents.
Key specs
| Isolation | Firecracker microVM |
| Cold start | 500ms |
| Price / vCPU-hr | $0.05 |
| Pricing model | Usage-based |
| GPU | No |
| Session limit | Configurable |
| Persistence | Git-versioned filesystem, forking |
| Languages | JavaScript/TypeScript, Node, others |
| MCP support | — |
| Integrations | REST/API |
| Deployment | Managed cloud |
| Free tier | Free tier |
| P95 cold start | 2.7s |
| Resume | ~500ms |
Strengths
- Git-versioned filesystem
- Sub-second forking
- Firecracker isolation
Trade-offs
- Web-dev-centric
- Mid-transition to Together branding
Best for: Web-development agents that fork and branch environments frequently.
Alternatives to CodeSandbox SDK
E2B — AI code-execution sandboxDaytona — AI code-execution sandboxModal — AI code-execution sandboxVercel Sandbox — AI code-execution sandbox
Sources: CodeSandbox SDK docs ↗
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