LangSmith Sandboxes are Generally Available

LangSmith Sandboxes entered general availability on 13 May 2026, offering hardware‑virtualized microVMs that are kernel‑isolated from services and other sandboxes. The sandbox platform provides snapshots and cheap copy‑on‑write forks, service URLs for authenticated HTTP access, a sandbox CLI for interactive consoles and file operations, and creator‑private authentication by default. New GA features include automatic pausing of idle sandboxes, allowlist/denylist domain controls, and an auth proxy that injects credentials at the network layer without exposing secrets to the runtime. Sandboxes integrate seamlessly with Deep Agents, Open SWE, LangSmith Deployment, and custom code, enabling agents to run untrusted code, install dependencies, and maintain state across long‑running sessions.

The release addresses security gaps highlighted by recent kernel exploits and supply‑chain attacks, providing true isolation that containers cannot match. Teams can now spin up parallel workloads, snapshot sandboxes from Docker images, and manage sandbox lifecycles entirely through the LangSmith SDK and API key, eliminating the need for separate runtime infrastructure.