Reverse Engineering Claude Code Reveals Anthropic's Undisclosed PaaS Platform Antspace: Built by Baku, Full-Stack Closed Loop Takes Shape

ArcBox Labs founder AprilNEA discovered Anthropic's undisclosed PaaS platform Antspace through reverse engineering Claude Code's runtime environment. Built by internal tool Baku, Claude Code runs on Firecracker microVMs with 4 vCPUs, 16GB memory, and 252GB disk, featuring a minimal process structure.

The analysis also found the AntspaceClient deployment client, supporting a three-stage deployment protocol, and Claude.ai web version defaults to deploying on Antspace instead of Vercel. Additionally, the platform supports enterprise BYOC environments, allowing businesses to run related programs on their own infrastructure. Experts assess that this architecture forms a vertical integration closed loop from model to hosting, competing with platforms like Vercel.