Senior Applied AI Engineer

About the role

This is an exciting opportunity to help shape how Pleo builds AI-powered product features, working alongside software engineers, data engineers and data scientists to take ideas from prototype to production. Pleo has over 40,000 customers and a decade of unique spend data — an incredible foundation to build on. Your mission will be to harness this data to create real product value.

Please note: applications will be open until 1st September 2026 at 09.00 CEST. We will not review any application before the window is closed so please take all the time you need to submit a great application!

Who you’ll be working with and reporting to

You'll be reporting to the Senior Manager for Data & AI Products and will be one of the first hires in the team but, rest assured, you will not be working solo! You will work very closely with other Engineers and Data Scientists, each bringing distinctive skills while you bring applied AI engineering and data context. Together, the team covers the full chain from data to shipped product.

Your core focus is on building and shipping AI-powered features, with a strong collaborative element across Product Engineering, AI Platform, and Data & ML Platform teams.

What you’ll be doing

As a Senior Applied AI Engineer you will:

• Build and ship AI-powered product features for Pleo’s customers, owning outcomes end-to-end for a scoped area.
• Design and build end-to-end RAG systems for specific product use cases: chunking strategies, embedding model selection, retrieval optimisation, and quality evaluation.
• Own the full AI-product lifecycle: prompt design, context and state management, agentic loops, output parsing, edge case handling, and safe production deployment.
• Build evaluation datasets and automated eval pipelines that give the team confidence in AI feature quality before and after changes.
• Instrument AI features for production observability: logging, drift detection, quality monitoring, and alerting.
• Collaborate with Product and Design to scope AI features from first principles; you are a co-author of what gets built, not just an implementer of specs.
• Partner with our GenAI Platform team to identify infrastructure needs and champion adoption of platform tooling.
• Support other engineers through reviews, pairing, and pragmatic technical leadership on the projects you lead.

What you bring

You will thrive in this role if you have:

• Proven experience shipping customer-facing AI features using LLMs; beyond prototype stage and into real production systems with real users.
• Deep practical experience with RAG system design and the full retrieval pipeline: embedding models, vector databases, chunking, hybrid search, re-ranking.
• Experience building and operating evaluation frameworks for LLM-based systems; you have a systematic approach to measuring quality.
• Strong Python engineering; your code is production-grade, tested, and maintainable.
• Experience building APIs and data retrieval pipelines that feed context into AI systems.
• Enough data intuition to reason about data quality, schema, and retrieval architecture without needing a dedicated data engineer beside you at all times.
• Experience with agentic system patterns: tool use, multi-step orchestration, error handling in LLM workflows.
• Familiarity with public cloud providers (AWS, GCP)
• We operate a polyglot platform, with components written in Kotlin and Python. While this role is Python-focused, you will need from time to time to contribute in a Kotlin stack, so being open to that is important.

Why is this role a good fit for you

This role is a good fit for you if:

• You have strong product instincts and build with the user in mind. You understand that a model is only as good as the problem it solves.
• You have moved past prototyping and have a deep understanding of the realities of LLMOps, data retrieval, prompt and context engineering, as well as model evaluation in production.
• You don't just call APIs, you understand the data feeding the AI system and can reason about data quality, architecture, and retrieval without needing a dedicated data engineer beside you at all times.

This role is not a good fit for you if:

• You are primarily interested in model research or algorithm development. This role is about shipping working AI features to production.
• You need fully defined specs and a groomed backlog to operate effectively. We expect you to discover and define the problem alongside Product and Design.
• You cannot explain AI trade-offs clearly to non-technical stakeholders. You will regularly work with Product Managers, Designers, and business leaders who need to understand what is and isn't possible.

How you’ll develop in this role

In your first 6 months at Pleo, you’ll:

• Familiarise yourself with our codebase, tooling and roadmap.
• Partner with our Principal Engineer to define and own our approach to AI feature development.
• Contribute to shaping the roadmap for tooling and features developed by our GenAI Core team.
• Collaborate with Product and Data teams to ship a first feature to production

We’re committed to helping you develop your career, whether that means taking on bigger projects, stepping into leadership, or acquiring new skills!