Full Stack Engineer

Pillar; Barcelona; On-site; EUR 65,000 - 80,000; Full time

Benefits offered by this job

Gross salary 65,000-80,000€

Real ownership of architecture and产品

AI-native team

Close to customers

Team that celebrates wins

Job summary

Pillar is hiring a backend-leaning Full Stack Engineer in Barcelona, onsite. You will own features end to end, shaping data models, APIs and integrations for payments and project finances, with a strong focus on backend architecture and scalable systems.

You will also contribute to frontend work in Next.js and React when needed, and apply AI to product building, debugging and learning, joining a small, autonomous squad in a fast-growing company.

Qualifications

• Experience building product in a startup or scaleup.
• Strong backend and databases; explain design decisions.
• Frontend fluency to own a feature end to end.

Responsibilities

• Own features end to end, from the customer problem to production.
• Design data models, APIs and integrations behind payments, invoices and project finances.
• Raise the bar on backend architecture across our TypeScript codebase.
• Work on the frontend in Next.js and React when the feature needs it.
• Use AI as a native part of how you build, debug and learn.

Skills

TypeScript

PostgreSQL

Next.js

React

Backend architecture

APIs design

Supabase

Tools

Supabase

Job description

Barcelona - Onsite

Pillar was founded in 2025. Today, we are 90+ people, serve 1000+ customers, raised €15.2M (pre-seed and seed round) and are expanding internationally.

We are building the financial operating system for construction: bringing AI, automation and modern software to an enormous industry still full of slow, fragmented processes.

We are looking for a backend-leaning Full Stack Engineer who has built product in a startup or scaleup, loves strong data models and wants to own features end to end.

The mission

Build product end to end, with particular strength on backend architecture and execution.

What You Will Do

• Own features end to end, from the customer problem to production.
• Design data models, APIs and integrations behind payments, invoices and project finances.
• Raise the bar on backend architecture across our TypeScript codebase.
• Work on the frontend in Next.js and React when the feature needs it.
• Use AI as a native part of how you build, debug and learn.

Who We Are Looking For

• You have built product in a startup or scaleup, ideally in the €3M to €30M growth stage, as part of a team of engineers and designers.
• You are strong on backend and databases, and you can explain why you made each choice, not just what you built.
• You are comfortable with Next.js, React, TypeScript, Postgres and modern backend patterns. Supabase is a strong plus.
• You have enough frontend fluency to own a feature end to end. Pure frontend profiles are not our focus for this hire.
• You understand an existing architecture before reshaping it, and you are open to patterns different from yours.
• You challenge ideas, accept trade-offs and make the people around you better.
• You are AI-native: AI is already part of how you build.
• Native Italian or Spanish, plus professional English. Based in Barcelona or willing to relocate

How We Work

• Small squads, high autonomy, no unnecessary layers.
• AI-first, in the product and in the way we build.
• Bottom-up: initiative is expected, not delegated.
• Pillar is not for you if you prefer to decide alone, or if you want to work only on frontend.

Hiring process

• 01 CV screening
• 02 30-min People call with Marta
• 03 30-min backend conversation with one of our engineers
• 04 30-min frontend and product conversation with another engineer
• 05 Final conversation with our CTO

What we offer

• Gross salary 65.000-80.000 €, based on experience
• Real ownership: from product decisions and architecture to features customers use every day
• A company that moves fast: 90+ people and 1000+ customers in under two years
• An AI-native team: AI is part of the product and of how we build it
• Close to customers: direct exposure to the problems we solve, with Product, AI and Engineering
• People who care: a team that celebrates wins together, gives honest feedback and has fun along the way.

Compensation Range: €65K - €80K