“When will Baseten offer sandboxes” has been a common customer question. And we’ve taken a huge step in answering it: Baseten has acquired Blaxel. The nature of the median inference call has changed in the past year. Models stopped just answering questions; they act now. A coding agent writes a patch, runs the test suite, reads the failure, and tries again, dozens of times to close a single ticket. Every one of those loops needs somewhere to execute code. And the agent itself needs its own runtime. And so do RL rollouts. The list goes on. Running some code in a container isn’t hard. The hard problem is storage (state), networking (milliseconds-long cold starts), and security (VMs). That's what Blaxel has built: stateful, pause/resumable, VM-isolated sandboxes that scale to thousands of instances in seconds. Zooming out, tomorrow’s cloud isn’t one of inference, training, or sandboxes. It’s one where these 3 primitives come together cohesively to meet users where they are and to unlock value that’s greater than the sum of the parts. That’s been the north star that Baseten and Blaxel share (they were in fact going to build inference and training). I couldn’t be more excited to do it together with Paul Sinai and team. Welcome 💚

Live inference data is the best training data for speculators. The hard part is training them online without storing hidden states or impacting inference performance and reliability. We built exactly that into the Baseten Inference Stack. Result: +20% median acceptance rates, with some domain-specific workloads improving by 100%.