Our client is a pioneering HealthTech scale-up developing a first-of-its-kind AI assistant designed by clinicians, for clinicians. They are tackling one of the most urgent global challenges: the critical shortage of healthcare professionals. By building a controllable and highly customizable 'AI brain,' they provide real-time, reliable support across the entire care continuum. This is a chance to work on a product where your code directly alleviates the burden on frontline medical staff.

As Senior AI Engineer, you will own and evolve the core "brain" service of this company platform. This is not about building simple wrappers; you will architect sophisticated multi-agent systems that reason and communicate in real-time via voice and text. You will tackle high-stakes challenges in low-latency streaming, autonomous orchestration, and continuous evaluation, shipping fast-moving Python services at the intersection of cutting-edge AI and human-centric health technology.

We can hire this position in UK or also in Spain (with valid work authorization for each country)

Main Responsibilities:

Core Intelligence Ownership: Lead the end-to-end architecture and evolution of the "core brain" service, taking full responsibility for SLAs, latency budgets, and deployment strategies.
Real-Time Voice & Text Systems: Design and operate low-latency communication systems featuring streaming voice/text, Voice Activity Detection (VAD), and complex interaction handling (barge-in, turn-taking, and interruptions).
Advanced Multi-Agent Orchestration: Build sophisticated multi-agent systems using planner–executor–critic patterns, shared memory, and advanced coordination protocols.
Reasoning Optimization: Implement and refine complex reasoning frameworks, including ReAct and Chain-of-Thought (CoT), as well as Tree/Graph-of-Thought architectures where applicable.
Automated Prompt Engineering: Leverage programmatic optimization tools (such as DSPy, MiPRO, or GEPA) to compile and evolve prompts iteratively under strict evaluation constraints.
High-Performance RAG Engineering: Develop robust Retrieval-Augmented Generation (RAG) pipelines focusing on high-signal retrieval, hybrid search, re-ranking, and query rewriting to ensure grounded and faithful AI responses.
Observability & Continuous Evaluation: Architect a comprehensive evaluation framework—from pre-call safety checks to post-call automated evals (hallucination detection, red-teaming)—using OpenTelemetry and structured logging to monitor drift and performance in real-time.
High-Velocity Backend Development: Ship high-quality, production-ready Python services using FastAPI, ensuring high performance and continuous integration/deployment (CI/CD) gates.

Requirements:

Core Backend: Extensive experience with Python, FastAPI, Pydantic, and asyncio for high-performance service development.
AI & Data: Proven track record with Multi-agent systems, Vector Stores, and advanced RAG architectures.
Infrastructure: Proficiency in Docker, Kubernetes (K8s), and Terraform for scalable deployments.
Real-Time Ops: Familiarity with STT/TTS (Speech-to-Text/Text-to-Speech) and monitoring via OpenTelemetry (OTEL).

Preferred Experience (Nice to Have)

Real-Time Communication: Hands-on experience with WebRTC stacks, LiveKit, and SIP gateways.
AI Evaluation: Deep dive into DeepEval or similar LLM-as-a-judge frameworks.
Prompt Optimization: Experience using DSPy for automated prompt compilation and self-improving workflows.

What's on offer?

Stability & Growth: Permanent contract with a long-term vision and deep investment in your professional journey.
Impactful Work: Build cutting-edge, real-time agent technology within a best-in-class HealthTech team where your code has a direct impact on global healthcare.
High-Octane Technical Environment: Join a highly motivating atmosphere that fosters continuous learning, peer-to-peer mentorship, and the freedom to experiment with the latest AI breakthroughs.
Flexibility & Balance: Truly flexible work-life integration with Remote-first or Hybrid options in our Barcelona hub. For people living in another Spanish cities the position can be remote.
Team Culture: Engaging team-building events and fun off-sites in Barcelona to connect with a diverse, international team.
Premium Tools: High-tech laptop of your choice and a budget for solid dev ergonomics to ensure your workspace is optimized for peak performance.
Continuous Learning: Access to the latest tools, research papers, and internal knowledge-sharing sessions on the frontier of Multi-agent systems and LLMs.

Our recruitment process?

Step 1: Interview with one of our recruiters

Step 2: Technical Interview with Hiring Manager

Step 3: Interview with another member of the team

Step 4: Cultural Fit Interview

Senior AI Engineer (with experience in Real-Time Voice & Text Systems)

Benefits