Baseten Sandboxes
Standby-and-resume sandboxes on the Baseten inference platform, built on the acquired Blaxel stack, with Python, TypeScript and Go SDKs, volumes and a free period until 16 November. An early, Blaxel-derived sandbox inside the Baseten platform that is attractive to existing customers but still thin on pricing and isolation detail.
Overview
Baseten, an inference and training platform, launched Sandboxes in November 2026 after acquiring the sandbox startup Blaxel. A sandbox is an isolated environment where an agent runs commands, background processes and file operations, created from built-in or custom images with 1-32 vCPUs and 1-8 GiB of memory per vCPU (default 2 vCPU/4 GiB). You manage it from Python (baseten), TypeScript (@basetenlabs/sandbox) or Go SDKs, the baseten sandbox CLI (marked pre-release), a management REST API, MCP clients or the dashboard. The docs do not name the isolation technology; Baseten said Sandboxes would be built on Blaxel's primitives.
Sandboxes go on standby when they stop receiving requests, keeping files and pausing processes, and resume on the next request; they expire after 7 days by default under configurable max-age, idle or date policies. Persistent volumes carry files between sandboxes within a region. There are no published paid prices: the docs state the product is free until 16 November with 10 concurrent sandboxes per organisation. The docs also include worked examples that train models with RL against sandboxed coding tasks, which is the platform's natural pairing.
Notable
- Built on technology from Blaxel, which Baseten announced it was acquiring in 2026
- Free to use until 16 November with a 10-concurrent-sandbox limit per organisation
- CLI sandbox commands are labelled pre-release
Baseten Sandboxes specifications
| Attribute | Details |
|---|---|
| Isolation | Docs say only "an isolated environment"; hypervisor not named. Baseten acquired Blaxel in 2026 and said Sandboxes would be built on its primitives (Blaxel documents microVMs) |
| Deployment | Hosted platform |
| Open source | No |
| SDKs and interfaces | Python, JavaScript/TypeScript, Go, CLI, REST API, MCP server |
| Cold start (vendor claim) | Not documented |
| Max session length | Sandboxes expire 7 days after creation by default; expiry policies are TTL_MAX_AGE, TTL_IDLE and a fixed DATE, one of each type, with no maximum stated |
| Persistence | Standby keeps files and pauses running processes until the next request; files are deleted on expiry or delete; persistent volumes (grow-only, one sandbox at a time, region-bound) keep files across sandboxes; custom images are versioned per team; no snapshot of a running sandbox documented |
| GPU | Not mentioned on the sandbox configure page; vCPU and memory only |
| Networking | HTTPS previews expose a web app in a sandbox via public or private URLs; short-lived sandbox access tokens for requests and MCP connections; no egress controls documented |
| Pricing | "Free to use until November 16" (docs, year not stated); no paid rates published |
| Free tier | Free until 16 November; up to 10 concurrent sandboxes per organisation, raisable via support |
| Compliance | Not documented |
| Regions | us-pdx-1 and us-was-1 appear in the docs; default is the closest region |
Facts from Baseten Sandboxes’s public documentation, verified November 9, 2026. Performance numbers are vendor claims.
Strengths and trade-offs
Strengths
- You run inference or RL training on Baseten and want agent sandboxes in the same account
- You want standby-and-resume with persistent volumes rather than ephemeral runs
- You need Go as well as Python and TypeScript SDKs
Trade-offs
- Isolation technology is not named in the docs
- No published paid pricing; only a free period until 16 November
- Concurrency limited to 10 per organisation by default
- No egress controls, snapshots or compliance statements documented for sandboxes
Good fit for: Coding and research agents on Baseten that need a persistent workspace with standby and volumes next to hosted models and RL training.
How Baseten Sandboxes compares
| Sandbox | Isolation | Open source | Self-host / BYOC | Cold start (vendor) | Max session | Snapshots / pause | GPU | SDKs |
|---|---|---|---|---|---|---|---|---|
| Baseten Sandboxes | Not named (Blaxel-based) | No | No / No | Not documented | 7 days default | No / Yes | Not documented | Python, JavaScript/TypeScript, Go, CLI, REST API, MCP server |
| Blaxel | MicroVM | No | No / Yes | <25 ms resume | Unlimited (standby) | Yes / Yes | Not documented | TypeScript, Python, Go |
| Modal Sandboxes | gVisor or VM | No | No / Not documented | <1 s | Up to 24 h | Yes / Yes | Yes | Python, JavaScript/TypeScript, Go |
| Beam Sandboxes | gVisor | Yes | Yes / Yes | ~0.5 s | Configurable | Yes / Yes | Yes | Python, TypeScript |
| Koyeb Sandboxes | MicroVM | No | No / Not documented | Not documented | Up to 24 h | Not documented / Not documented | Yes | Python, JavaScript/TypeScript |
| Northflank Sandboxes | Cloud Hypervisor microVM | No | No / Yes | <1 s | Unlimited | Not documented / Yes | Yes | JavaScript/TypeScript, Python |
| Fly.io Sprites | MicroVM | No | No / No | 0.1–2 s wake | Unlimited | Yes / Yes | No | JavaScript/TypeScript, Go, Python, Elixir |
Frequently asked questions
What is Baseten Sandboxes?
How does Baseten Sandboxes isolate code?
Is Baseten Sandboxes open source?
How much does Baseten Sandboxes cost?
What are the alternatives to Baseten Sandboxes?
Sources
- docs.baseten.co/sandboxes/overview.md
- docs.baseten.co/sandboxes/manage.md
- docs.baseten.co/sandboxes/configure.md
- docs.baseten.co/sandboxes/lifecycle.md
- docs.baseten.co/sandboxes/volumes.md
- docs.baseten.co/_llms/documentation.txt
- baseten.co/blog/blaxel-is-joining-baseten-to-build-the-future-of-agentic-cloud/
Cite this page
Agent Sandboxes. (2026). Baseten Sandboxes. agentsandboxes.org. Last reviewed November 9, 2026. https://agentsandboxes.org/sandboxes/baseten-sandboxes/
Found an error or a missing sandbox? Submit a correction — every entry links to the sources it relies on.