Senior Software Engineer, Voice AI / Backend

ABOUT THE ROLE Join a small, high-velocity engineering team building voice AI agents for customer-facing workflows. You will own projects end to end, from product decisions and system design to production code, across applied AI, real-time audio, and distributed systems. WHAT YOU'LL DO - Build reliable voice AI systems, including retrieval-augmented generation, dynamic language model routing, and testing new transcription systems before release. - Design and operate distributed call scheduling systems that handle concurrency, time zones, retries, provider limits, and failure recovery. - Extend agents across voice and other communication channels, maintaining shared context between real-time and asynchronous interactions. - Develop memory and reasoning systems that help agents retain context across customer workflows. - Build AI tools that configure agents, diagnose issues, and connect with customer relationship management systems, calendars, and email. - Improve tracing and observability so production issues can be diagnosed and resolved effectively. WHAT WE'RE LOOKING FOR - Production experience building and owning distributed systems, with strong software fundamentals and a track record of delivering projects end to end. - Experience as a product engineer building customer-facing systems, rather than working exclusively in machine learning or data roles. - Production experience with Python, FastAPI, or TypeScript, and with PostgreSQL, Redis, or similar data stores. - Experience with real-time systems, audio processing, or voice infrastructure, as well as distributed systems challenges such as concurrency and fault tolerance. - Experience with language models, AI agents, or similar systems in production, and cloud infrastructure such as AWS, GCP, or Azure. - Familiarity with tools such as LiveKit, Temporal, message queues, React, and OpenTelemetry is useful. The broader stack includes Bun, Node.js, Fastify, and observability platforms. - Independent, action-oriented approach, sound judgment about code quality and reliability, and a focus on team and business outcomes. COMPENSATION & BENEFITS Annual compensation is €85,000 to €160,000, plus equity. Visa sponsorship is available. LOCATION On-site in Berlin, Germany. Relocation support is available.