Every session runs in its own isolated sandbox. Sandboxes are ephemeral: spun up for the session, destroyed when it’s done. No code or state persists after execution.
Data handling
Your repository is cloned into the sandbox for the duration of a session and torn down when the session ends — no repository contents or working state persist afterward.
The one exception is snapshots. If you use the snapshot feature to speed up environment setup, your repository and pre-installed dependencies are cached into a reusable snapshot image so future sessions start faster. That cached copy persists until the snapshot is rebuilt or removed.
Model providers handle prompt data according to their own retention policies — see the retention table in Max for Tembo-hosted models. With BYOK, model requests run against your own provider account, so provider-side retention follows that account’s terms.
Sandbox sizes
Tembo offers five sandbox sizes. Each session runs in a dedicated Linux VM, and no two sessions share the same VM.
| Size | vCPU | Memory | Disk |
|---|
| Micro | 2 | 4 GB | 50 GB |
| Medium | 4 | 8 GB | 50 GB |
| Large | 8 | 32 GB | 100 GB |
| XL | 16 | 64 GB | 200 GB |
| Ultra | 32 | 128 GB | 200 GB |
| Category | Tools |
|---|
| JavaScript | Node.js 22, Bun, pnpm, Yarn |
| Python | Python 3.12, pipx, uv, ruff |
| Ruby | Ruby 3.3, Bundler, RuboCop |
| .NET | .NET SDK 9 |
| Cloud | Google Cloud SDK |
| Containers | Docker 28, Docker Compose 2.31 |
| Other | Git, curl, ShellCheck, httpie |
Go, Rust, Java, and Elixir are available through Nix dev shells. Add a tembo.nix to install language-specific tooling for your project.
Add custom dependencies
Add a tembo.nix file to your repository when your project needs tools that are not pre-installed in the sandbox. 
