Staff Engineer, GenAI Core

At Pleo, we're on a mission to make spend management surprisingly effective and empowering.

We're hiring a Staff Engineer to join the GenAI Core team. You will help set technical direction for Pleo's AI platform, the shared infrastructure that enables product teams across the company to build AI-powered features reliably and at scale.

What GenAI Core does

GenAI Core owns and operates Pleo's AI platform infrastructure. We are the team that makes it possible for every other product team at Pleo to build AI-powered features, reliably, observably, and without reinventing the wheel.

That means:

• LLM routing and access: a centralised LLM proxy layer (LiteLLM) that routes requests to different model providers (Azure OpenAI, AWS Bedrock, Google Gemini), with budget enforcement and rate limiting
• Observability and evaluation: integrations and tooling (BrainTrust) to monitor, log, and evaluate LLM calls in production, supporting both automated evaluation and human review
• Platform standards and guidance: we define how AI is done at Pleo, providing patterns, contracts, and shared components that product teams build on
• Internal consulting: as product teams across Pleo adopt AI capabilities, GenAI Core will increasingly act as a technical partner, helping teams design and implement AI features correctly on top of the platform

This is software engineering work. While the domain revolves around AI infrastructure, you will spend most of your time building reliable, scalable backend systems.

What you’ll be doing

In this role, you will be a force multiplier for platform quality and technical direction.

• Drive the design, delivery, and evolution of the GenAI Core platform, the shared AI infrastructure used by all product teams at Pleo
• Own and evolve service architecture, APIs, and integration contracts, with a high bar for reliability and observability
• Set technical direction for key parts of the platform, including LLM routing, budget enforcement, observability pipelines, and evaluation infrastructure
• Lead cross-team technical initiatives and act as a trusted technical partner when product teams need to build AI-powered features on top of the platform
• Raise the engineering bar through strong practices: code reviews, incident follow-ups, safe change management, and resilient system design
• Proactively identify and address technical debt, and guide the team through architectural decisions and migrations
• Support other engineers through pairing, reviews, and technical guidance
• Contribute hands-on in code. You should expect to be coding a meaningful part of the time.

You’ll bring solid experience with

• Designing and maintaining backend systems with strong requirements for reliability and observability
• Building and operating a shared platform or infrastructure components used by multiple teams
• Distributed systems fundamentals, including async workflows, idempotency, consistency, and designing for failure
• API design, clear service boundaries, and integrating with external systems in a maintainable way
• Observability and owning systems in production, including monitoring, alerting, incident response, and post-mortems
• Strong testing practices and a high quality mindset
• Clear communication and pragmatic decision-making across teams and stakeholders

Nice to have

• Hands-on experience working with LLM APIs (OpenAI, Anthropic, AWS Bedrock, or similar) in a production system
• Familiarity with LLM evaluation patterns such as LLM-as-judge, vector similarity, and sampling strategies
• Experience building or operating proxy or routing layers for AI workloads

Your colleagues would say you

• Lead by example and raise the bar with pragmatism and care
• Communicate clearly, listen well, and bring people along in decisions
• Enjoy breaking down complex problems, gathering input, and driving to a solution
• Coach and mentor others and create space for people to grow
• Prefer progress over perfection, while still caring deeply about quality

Show me the benefits!

• Your own Pleo card (no more out-of-pocket spending!)
• Lunch is on us for your work days - enjoy catered meals or receive a lunch allowance based on your local office 🍜
• Comprehensive private healthcare - depending on your location, coverage options include Vitality, Alan or Médis
• We offer 25 days of holiday + your public holidays
• For our Team, we offer both hybrid and fully remote working options
• Option to purchase 5 additional days of holiday through a salary sacrifice
• We use MyndUp to give our employees access to free mental health and well-being support with great success so far ❤️‍🩹
• Paid parental leave - we want to make sure that we're supportive of families and help you feel that you don't have to compromise your family due to work 👶