Senior Platform Engineer - On-Site SF, Stateful Runtimes

Sauna By Wordware in San Francisco is seeking a senior backend engineer to build the execution engine behind agent sessions. You will implement how work starts, carries session state through tool calls, and resumes after interruptions, owning the production code from day one. This role emphasizes deciding when work should be an actor or a job, designing long-running processes across releases, and making runtime failures traceable.