Principal Engineer - AI/ML

Then Just Eat Takeaway might be the place for you. We’re a leading global online delivery platform, and our vision is to empower everyday convenience.

Whether it’s a Friday-night feast, a post-gym poke bowl, or grabbing some groceries, our tech platform connects tens of millions of customers with hundreds of thousands of restaurant, grocery and convenience partners across the globe.

We are building the next evolution of intelligent systems. Moving from isolated models toward a unified, agentic ecosystem. As a Principal Engineer, you will design and lead the development of our Cognitive Operating System: the core infrastructure enabling autonomous agents to reason, learn, and operate at scale.

You’ll sit within a high-impact engineering leadership group, partnering closely with Product, Data, and Engineering leaders to shape AI-native capabilities. This role embodies our values of lead, deliver, and care by driving innovation while fostering collaboration and shared success.

This is a defining opportunity to influence a major technology shift, helping transition from traditional software to adaptive, intelligent systems that continuously improve and deliver value for our customers.

• Architect and evolve the Cognitive Runtime, enabling multi-step reasoning, tool usage, and self-correcting agent workflows.

• Build and standardise a Skill Catalog so agents can discover and interact with internal APIs and legacy systems seamlessly.

• Design scalable memory and context systems, bridging short-term interactions with long-term organisational knowledge.

• Develop next-generation AI infrastructure optimised for high-throughput inference, GPU orchestration, and non-deterministic workloads.

• Lead Continuous Evaluation frameworks, including automated testing, LLM-as-a-judge systems, and real-time safety monitoring.

• Create feedback loops that capture agent interactions to continuously improve model performance and system intelligence.

• Collaborate with data teams to build low-latency pipelines that transform raw data into retrieval-ready knowledge for AI systems.

• Define semantic governance standards, including embedding strategies, versioning, and caching for reliable agent performance.

• Influence engineering teams to adopt agent-ready architectures, ensuring systems are interoperable and machine-readable.

• Provide technical leadership on AI ethics, security, and cost efficiency, helping teams deliver responsibly at scale.

• Deep expertise in agentic frameworks (e.g. LangGraph, CrewAI, AutoGen) or custom multi-agent orchestration systems.

• Strong experience with vector databases, graph databases, and knowledge graph-based retrieval systems.

• Proven ability to design and scale AI infrastructure, including inference systems, GPU orchestration, and fine-tuning pipelines.

• Solid background in distributed systems, event-driven architectures, and high-scale backend engineering (Python, Go, or Rust).

• Strong collaboration skills, working closely with product, data, and engineering leaders to deliver shared outcomes.

• Ability to simplify complex systems and create clear, scalable architectural patterns for broader adoption.

• Experience building platforms that continuously learn and improve through data feedback loops.

• A mindset focused on innovation, challenging the status quo and driving forward-thinking technical solutions.

• Strong sense of ownership and accountability, balancing speed with quality and long-term impact.

• Passion for shaping the future of AI, with a responsible approach to ethics, safety, and system reliability.

Our teams forge connections internally and work with some of the best-known brands on the planet, giving us truly international impact in a dynamic environment.

Being the best at what we do isn’t just about delivering on our strategy. It's a competition for something incredibly valuable – our customers' choice. Every time a customer decides where to order, they're picking a side.

At the heart of the JET Customer League are our values and behaviours. They guide every interaction, every decision, every innovation. These are the actions we need to perform consistently and brilliantly, to surpass the competition and earn our customers’ loyalty, again and again.

Fun, fast-paced and supportive, the JET culture is about movement, growth, helping one another to succeed and celebrating wins. By truly living our values and embodying our behaviours, we’re building a customer-first culture which enables us to stay one step ahead of the competition.

No matter who you are, what you look like, who you love, or where you are from, you can find your place at Just Eat Takeaway. We’re committed to creating an inclusive culture, encouraging diversity of people and thinking, in which all employees feel they truly belong and can bring their most colourful