Baseten buys Blaxel, a startup that builds sandboxes for AI agents

AI inference company Baseten has acquired Blaxel, a startup that builds secure execution environments, or sandboxes, for AI agents. Baseten co-founder and chief technology officer Amir Haghighat told Axios Pro about the deal, which the outlet reported first on Thursday. Baseten later announced the acquisition.

Axios describes Blaxel as a San Francisco startup. The announcement did not disclose financial terms.

What Blaxel builds

Blaxel builds sandboxes based on microVMs, small isolated virtual machines. Each agent gets its own. According to the release, the sandboxes spin up and resume up to five times faster than competing products.

In a joint blog post, the companies said a Blaxel sandbox can suspend and resume in 25 milliseconds. It can also sit idle for months at close to zero cost.

Its other products include Agent Drive, a distributed filesystem that agents can share, and a networking layer that connects agents to tools, MCP servers, APIs and other agents. The team has been building the platform for more than 18 months, the post said.

What changes for customers

According to the post, Blaxel will continue to operate and its product does not change. Baseten will add new products based on Blaxel’s technology, starting with sandboxes.

In the near term, Blaxel’s technology expands Baseten’s support for code execution, tool use and session persistence, the release said. Over time, Baseten plans to integrate it with its inference, storage, observability and enterprise infrastructure.

“Agents need models, but they also need a secure environment to run in that’s fast, scalable, and reliable enough for production,” Haghighat said in the release.

Paul Sinaï, Blaxel’s co-founder and chief executive, said: “We started Blaxel because agents need environments designed to work alongside the models powering them.”

Baseten’s run of deals

Baseten, founded in 2019, has raised more than $2bn. In June, TNW reported that it raised $1.5bn at up to $13bn. The release puts the valuation of that Series F round at $13bn.

In December 2025, Baseten acquired Parsed, a reinforcement learning startup. Its customers include Abridge, Clay, Cursor, Lovable, Mercor and OpenEvidence, according to the company.