Blaxel Acquired by Baseten
Baseten has acquired Blaxel (blaxel.ai), the sandbox platform that gives AI agents isolated environments to run code and use tools. Terms were not disclosed. Axios reported the deal ahead of Baseten's announcement Thursday morning.
Blaxel runs each sandbox inside its own microVM, on a forked Firecracker runtime, so agent-generated code executes behind a hardware-enforced kernel boundary. The company's distinguishing feature is lifecycle behavior: sandboxes sit in standby indefinitely without accruing compute charges and resume in roughly 25 milliseconds with filesystem and memory state intact, which matters for agents that pause for hours between turns and then need their working context back. Alongside sandboxes, the platform hosts agents, batch jobs and MCP servers, and carries SOC 2 Type II.
The company was founded by Paul Sinaï, who previously built and sold ForePaaS to OVHcloud, together with five colleagues from OVHcloud and ForePaaS: Christophe Ploujoux, Nicolas Lecomte, Thomas Crochet, Charles Drappier and Mathis Joffre. Blaxel went through Y Combinator in the Spring 2025 batch and raised a $7.3M seed a few months later, led by First Round Capital with Pioneer Fund, Y Combinator, Liquid 2, Transpose, Multimodal, Tekedia Capital and a group of angels participating.
The logic of the deal comes down to where the two halves of an agent workload live. A model can produce a plan, but something else has to execute it, and most teams today buy inference from one vendor and execution from another. Every hop between those systems adds latency and leaves state to be managed by hand. Baseten's framing is that inference is the brain and the sandbox is the muscle, and that owning both puts the whole agent runtime on one system.
Baseten has been assembling that stack through acquisitions for the better part of a year. It bought Parsed, a reinforcement learning team focused on post-training and continual learning, in December 2025, and signed a collaboration agreement with AWS the same month. In June it raised a $1.5B Series F at a $13B valuation, led by Altimeter Capital, Conviction and Spark Capital, with Sands Capital and Wellington Management as co-leads. At the time of that round the company said revenue had grown 20x over the prior year and inference volume 40x, running across 87 clusters and 18 cloud providers.
The Blaxel team joins Baseten, where the sandbox product becomes the execution layer sitting next to Baseten's inference stack.