Senior AI Engineer

Our client is redefining how humans and machines communicate - building AI-powered voice agents that handle real conversations with speed, clarity, and empathy. Their platform automates millions of phone calls, helping businesses save time, respond faster, and deliver more human-like experiences at scale. Trusted by 1,000+ customers and backed by leading VCs, their voice agents have already powered over 55 million calls with 99.9% uptime - transforming the future of how people interact with businesses.

As a Senior AI Engineer, you’ll be at the core of this mission — designing and deploying ultra-low-latency speech pipelines that sit at the intersection of Automatic Speech Recognition (ASR), Large Language Models (LLMs), and Text-to-Speech (TTS). You’ll own the ML systems that bring natural, multilingual conversations to life - bridging real-time voice input with advanced inference and high-quality speech synthesis.

• Architect and implement real-time pipelines: ASR → LLM → TTS, optimised for latency, clarity, and conversational flow.
• Evaluate, fine-tune, and deploy state-of-the-art models across ASR, LLMs, and TTS - from open-source to commercial.
• Optimise inference with techniques like quantisation, distillation, and hardware-aware graph compilation.
• Build scalable APIs and microservices (Python/FastAPI, gRPC, WebSockets) with autoscaling and observability baked in.
• Deploy to both cloud and on-premise environments (Kubernetes, Docker), using CI/CD and infrastructure-as-code.
• Stay on the cutting edge - run experiments, evaluate emerging tools, and share insights with the wider ML team.

• Python Engineering - Strong background in production-grade Python (async, typing, profiling).
• Speech/Audio Systems – Hands-on experience with at least one of the following: ASR, TTS, STT, streaming voice pipelines, or audio-based applications.
• LLM Experience - Familiarity with fine-tuning, prompt engineering, retrieval-augmented generation (RAG), and tools like OpenPipe/ART, LangChain, or LlamaIndex.
• Start-up Experience - Prior experience working in a start-up environment.

If you’re excited to shape the future of voice interaction - making machines speak, listen, and understand like never before - we’d love to hear from you.