Senior AI Engineer

Time to Hire; Portugal; On-site; EUR 70,000 - 100,000; Full time

Job summary

Time to Hire in Lisbon, Portugal is seeking a Senior AI Engineer to build AI agents for a fintech startup. You will design AI agents, integrate LLMs with tools, and deploy production-grade AI systems in a fast-growing European fintech.

You will work on reliable AI architectures, evaluation, and performance optimizations, collaborating with engineers to ship end-to-end AI solutions for accounting tasks and workflows.

Qualifications

• Production systems experience (APIs, databases, distributed systems).
• Experience shipping LLM applications: tool calling, agents, workflows.
• Knowledge of testing nondeterministic systems.
• Pragmatic approach: AI fit vs traditional software.
• Ownership from idea to production; professional English.
• No ML research or accounting background required.

Responsibilities

• Design AI agents and workflows using LLMs, tools, and data.
• Ensure reliability of AI in production with deterministic logic.
• Build evals, identify failure modes, and improve accuracy and cost.
• Develop APIs, integrations, long-running AI workflows (Python, Django, PostgreSQL, GCP).
• Shape the company's AI architecture and engineering practices.

Skills

Production systems

LLM apps

Agent workflows

Nondeterministic testing

Ownership mindset

English proficiency

Tools

APIs

Databases

Distributed systems

Job description

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.