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Phonely | Senior Backend Engineer (Python) | San Francisco (Onsite) | Full-time
We’re building the future of voice AI for businesses, with a platform designed to make real-time agents easy to build, tune, and operate.
About the Role
We’re looking for a senior backend engineer to work on core systems that drive live voice conversations in production. This is a hands-on role with a lot of ownership and a lot of Python.
What You'll Do
- Build Python-based state systems for real-time voice AI conversations
- Integrate multiple LLM providers (prompting, routing, tool calling, fallbacks)
- Write high-performance async Python (FastAPI, asyncio)
- Design and test resilient agent logic and microservices
- Operate and improve production systems with strong observability
What We're Looking For
- 5+ years of Python experience, including async web services
- Experience with FastAPI, testing, and CI/CD
- Strong system design and security fundamentals
- Familiarity with LLMs, cloud infrastructure, AWS, and Kubernetes
Stack
Python, FastAPI, async microservices, AWS/GCP, Kubernetes, Redis, Firebase, Supabase, Datadog, SIP/voice APIs
Why Phonely
- Small, intense team of builders
- High ownership, fast pace, real impact
- In-office 5 days/week in SF
- Company-paid meals, great culture and periodic international work trips
https://www.ycombinator.com/companies/phonely/jobs/gp1xSAu-s...