JOIN KLEO AND BUILD THE FINANCING INFRASTRUCTURE FOR EUROPE'S COMPANIES Kleo ( is an AI-native platform that helps compaies find, match, manage, and monitor their entire financing stack: public grants, bank lending and private capital, through automated, end-to-end workflows. We replace a process that has traditionally depended on slow, manual, relationship-driven intermediaries with software.
We're growing fast and we're looking for a talented Senior Backend Engineer to join the engineering team and help us scale across Europe.
Play a key role in building and optimizing Kleo's platform using NestJS, TypeScript, PostgreSQL, REST APIs, AWS and more.
Integrate AI and LLM solutions to automate financing workflows and push platform performance further.
Work across both coding and DevOps, contributing to the full product lifecycle from code to deployment.
Seniority: a senior engineer who owns development end to end, from design decisions to production, and is comfortable being accountable for what ships.
Strong track record in web software development,



with the judgment to make sound architectural calls and the willingness to keep learning in a fast-paced startup. Advanced PostgreSQL: query optimization, indexing strategy, execution-plan analysis and modelling for data-intensive workloads is a core part of the role, not a nice-to-have.
Strong AWS and cloud-native experience, with a DevOps mindset across the full lifecycle (containers, CI/CD, observability).
English: a real intermediate-high level, especially for technical communication. No formal certification needed, but you should be able to understand and communicate technical information in English comfortably.
It doesn't matter. Hybrid model: 2 days in the office in Madrid (Cuzco area) and 3 days from home.
Christmas, Easter and summer are full remote if you want, August and every Friday are short-day (jornada intensiva).
We're on a mission to fix financing for companies, using AI to remove the complexity and ineffi

📌 Senior Backend Engineer (Madrid)
🏢 Kleo
📍 Madrid