Senior AI Engineer | Voice

We’re seeking a driven Senior AI Voice Engineer to join one of the fastest-growing legal tech companies in Europe as we expand our core AI team delivering ‘Marie’, our AI phone assistant. This role focuses on production voice AI systems operating over real telephony infrastructure — building, maintaining, and scaling phone agents that handle real customer conversations at production volume. You'll own the complete voice stack, from telephony and speech systems through to LLM orchestration, tooling, evaluation, and observability. Reporting to the AI Lead , you’ll work hands-on from architecture to implementation, collaborating with the Head of Engineering and product teams to ship reliable AI functionality while improving our voice infrastructure, evaluation workflows, and AI platform capabilities. For an engineer who has personally shipped production phone agents and end-to-end LLM-powered products , this is an opportunity to take technical ownership of Marie, ship quickly, and shape how voice AI evolves across the company. Your Challenge and Opportunity in This Role You’ll help define how voice AI is built and operated in a fast-moving product environment. As a core Senior AI Voice Engineer, you’ll turn modern voice and generative AI technologies into production-ready systems that deliver real value to users. Your primary goal will be to maintain, improve, and expand our phonebot platform. Expect strong technical ownership, fast iteration, and a clear focus on building reliable voice systems that operate effectively in real-world telephony environments. Tasks AI Strategy & Implementation: Architect and implement production-ready generative voice AI solutions within our product suite Develop voice-based AI systems , integrating speech technologies such as ASR/STT and TTS into conversational workflows Design and optimize real-time voice agent workflows , balancing latency, reliability, and conversational quality Architect and implement production-ready generative AI and LLM-based solutions to power voice experiences end-to-end Implement evaluation, testing, and observability for AI systems to ensure reliability and continuous improvement Establish best practices for AI development, testing, and deployment across products Handle AI development hands-on as a core technical contributor within a small, fast-moving team where engineers own problems end-to-end and ship quickly Cross-functional Collaboration: Work closely with product, design, and engineering teams to integrate AI capabilities into real product workflows Partner with stakeholders to define and improve user experiences across voice, telephony, and AI-driven interactions Translate complex AI concepts into practical product features and communicate them clearly to both technical and non-technical stakeholders Requirements Technical Expertise: 5+ years of software engineering experience 1–2+ years of hands-on experience building and operating production Voice AI systems Proven experience building and shipping production phone agents handling real users and real phone calls Hands-on experience with at least one major voice-agent framework or provider such as LiveKit Agents, Vapi, Pipecat, Retell, Daily Bots, Bland, OpenAI Realtime, Twilio, Telnyx, Deepgram, Soniox, ElevenLabs, or Cartesia Strong understanding of the complete voice pipeline, including STT, LLM orchestration, TTS, turn-taking, interruption handling, and latency optimization Strong understanding of telephony concepts including PSTN, SIP, and WebRTC Experience building LLM-powered products end-to-end , including prompt engineering, RAG, tool/function calling, model selection, and evaluation Experience with LLM observability and evaluation tools and designing evaluation pipelines for AI systems Strong programming skills in Python and solid software engineering practices Experience implementing AI systems in real production environments , not purely research or academic settings Nice to Have: Experience operating high-volume outbound calling systems , including concurrency management, retries, and compliance considerations Experience deploying OpenAI Realtime API or Gemini Live into production environments Experience with voice evaluation and observability platforms or custom evaluation frameworks Fluency or working proficiency in European languages such as German, French, Spanish, or Italian Experience contributing to or participating in voice AI communities and open-source projects Note: You must be located in the CET -2/+2 timezone for this role! Benefits 🚀 Foundational Impact – Help build and scale the core AI capabilities of JUPUS from the ground up 🔒 Technical Ownership – Work directly on the systems powering AI features across multiple products 🌱 Growth Environment – Build production AI systems at the cutting edge of generative AI and agentic workflows 💼 Leadership Visibility – Flat hierarchy with direct access to the Head of Engineering and CTO, reporting to the AI Lead 🏡 Fully Remote – Enjoy the flexibility of working from anywhere 💻 Top Equipment – State-of-the-art MacBook plus all the accessories you need 🏋️ Wellbeing Perks – Urban Sports Club membership to support your healthy lifestyle If you're passionate about building production voice agents, solving real-world telephony challenges, and creating intelligent AI systems that users rely on every day, we’d love to hear from you.