Senior Full Stack Engineer (Back-End)

San Francisco. Posted 8 months ago

The role

You will write and ship full-stack features end to end, from agent runtime and backend APIs to web and desktop UI. You will work directly with the CTO to build sandbox infrastructure, design deployment pipelines, and instrument real-time workloads.

What you will do

Build and operate the sandbox infrastructure where agents execute code
Design the deployment and migration pipeline for a Cloudflare Workers + Fly.io architecture
Instrument real-time workloads end to end
Ship new backend capabilities, tool integrations, scheduled task execution, and memory indexing
Reduce operational toil for a small team
Build whatever else needs building

Required qualifications

5+ years of engineering experience building and operating backend systems in production
Experience being on-call
Fluent in TypeScript
Comfortable working across the stack
Built real-time systems: WebSockets, SSE, event streaming, or message queues in production
Distributed systems intuition
Shipped infrastructure to real users

Nice to have

Worked with Cloudflare Workers, Durable Objects, or serverless compute at the edge
Built agent systems, model routing layers, or tool-use architectures with LLMs
Been a founder or early-stage engineer

Benefits

health
dental
401(k)
considerable PTO
gym budget
lunch

Before you apply

Must be based in the Bay Area or willing to relocate before starting
Require US work authorisation, but open to O-1 or J-1 visa sponsorship for exceptional candidates
Process includes a paid work trial

About the company

Sauna is a hybrid of AI and software. Wordware is the team behind it, 15 people backed by Spark Capital, Felicis, and Y Combinator.