Senior AI Engineer – Build AI agents for a fintech startup | Lisbon (on-site)

Want to take LLM agents from prototype to production in a product that real businesses trust with their finances? A fast-growing European fintech startup is building an AI-native accounting platform for SMEs, and is looking for a Senior AI Engineer to help build its core AI systems.

What you'll do

• Design AI agents and workflows that use LLMs, tools and structured data to automate complex accounting tasks.

• Make AI reliable in production by combining LLMs with deterministic logic, validation and human oversight.

• Build evals, find failure modes, and improve accuracy, latency and cost.

• Develop the APIs, integrations and long-running workflows behind the AI (Python, Django, PostgreSQL, GCP).

• Help shape the company's AI architecture and engineering practices.

What we're looking for

• Solid software engineering background building production systems (APIs, databases, distributed systems).

• Hands-on experience shipping LLM applications: tool calling, agents or agentic workflows.

• Know-how in testing and evaluating nondeterministic systems.

• A pragmatic mindset: you know when AI fits and when traditional software is better.

• Ownership from idea to production, and professional English.

• No ML research or accounting background required.

Location and schedule

Lisbon, Portugal · In-office, 5 days a week · Full-time. Early-stage team, real impact, and an AI-first way of working. If you want to build AI that has to be right, apply now and our Time To Hire recruiting team will contact you.