At Sumary, we are rebuilding finance from first principles.

We are an AI-native fintech backed by the largest fintech pre-seed round ever raised in Denmark, on a mission to eliminate broken financial workflows and define the future of autonomous finance.

This is a rare opportunity to join at the very beginning - to help build a new category of financial infrastructure, ship real product used by leading accounting firms, and shape how finance teams across Europe will work in the coming decade.

As a Founding Full-Stack Software Engineer at Sumary, you will build, refine and ship AI-native financial workflow products used by bookkeepers, controllers and finance teams across Europe.

Come help define and build the future of finance.

What you will be doing

• Architect and implement features end-to-end

• Take real ownership of our codebase, balancing robustness, security and speed

• Work with technologies such as TypeScript/React/Next.js, Node.js, Postgres/Supabase, Temporal, Modal and AI service layers

• Design and evolve our internal platform, from data pipelines to workflow engines

• Drive continuous improvement and challenge us, the product and yourself

• Collaborate directly with founders, users and accounting firms to shape the real workflows we automate

Who you are

• A passionate engineer with 3-5 years of experience building real products end-to-end

• Comfortable across the entire stack

• You are autonomous, resourceful and thrive with ownership

• A problem solver who can think holistically about system design

• Knowledgeable about AI and agentic workflows

• Experience with infrastructure, integrations, or financial/ledger data is a plus (but not required)

Why this role

• Build foundational systems in a massive category ready for transformation

• Ship fast and see immediate real-world impact from bookkeepers and finance teams

• Join early, influence architecture, culture and engineering standards

• Work directly with second-time founders backed by byFounders, Partech, Tenity and top angels

• Help define what autonomous finance looks like in the coming decade