Senior Software Engineer, Voice AI / Backend

ABOUT THE ROLE Join a small engineering team building voice AI agents for customer-facing workflows. You will own projects end to end, from technical design through production, across applied AI, real-time audio, and distributed systems. WHAT YOU'LL DO - Build reliable voice AI systems, including retrieval, dynamic model routing, and testing speech transcription systems before production rollout. - Design and operate distributed call scheduling systems that handle concurrent workloads, time zones, retries, race conditions, and provider limits. - Extend agents across voice, messaging, and email, maintaining shared context between real-time and asynchronous interactions. - Develop memory and reasoning systems that preserve context across customer workflows. - Build tools that help configure agents, debug issues, and connect to CRM, calendar, and email systems. - Improve tracing and resilience so teams can identify call failures and respond to issues with workers or providers. WHAT WE'RE LOOKING FOR - At least 2 years of experience building and owning production software, including distributed systems and end-to-end product delivery. - Production experience with Python, FastAPI, or TypeScript, plus PostgreSQL, Redis, or similar data stores. - Experience with real-time systems, audio processing, or voice infrastructure, and with LLMs, AI models, or agentic systems in production. - Knowledge of distributed systems concepts such as race conditions, load balancing, and fault tolerance, plus experience with AWS, GCP, or Azure. - Familiarity with workflow orchestration or messaging tools such as Temporal, and observability tools such as OpenTelemetry or Honeycomb. - Full-stack experience with tools such as React is useful. Strong software fundamentals, independent problem-solving, and a focus on customer and business outcomes are important. - Technologies include Python, FastAPI, LiveKit, TypeScript, Bun, Node.js, Fastify, React, PostgreSQL, Redis, Temporal, and major cloud platforms. COMPENSATION & BENEFITS Compensation is €85,000 to €160,000 annually, plus equity. Visa sponsorship is available. LOCATION On-site in Berlin, Germany.