Our client, a fast-growing international startup, is redefining how people unlock the value of what they already own, turning circularity into a smart, frictionless payment experience. With a live product, real traction, and a modern tech stack, they are expanding their engineering team with a senior backend profile who enjoys building scalable, resilient systems that have a direct impact on business.
If you’re motivated by real technical challenges, modern architecture, and building AI-driven features from the ground up (not just buzzwords), keep reading.
The Role
The selected candidate will join an agile team with real autonomy. Core responsibilities include:
* Designing and building scalable backend systems (Python + Django REST Framework).
* Working on complex integrations across payments, ecommerce, logistics, and automation.
* Participating in architectural decisions and technical roadmap definition.
* Driving engineering quality through testing and TDD practices.
* Mentoring teammates and contributing to product direction.
* Helping build the AI infrastructure from scratch.
What We’re Looking For
Technical Background
* 5+ years of backend development experience (senior or lead level).
* Strong experience with Python and Django REST Framework (or similar: Ruby on Rails, Phoenix, Laravel, etc.).
* Strong testing mindset (ideally TDD).
* Knowledge of PostgreSQL, AWS, and security best practices.
* Comfortable with occasional frontend work (while remaining backend-focused).
* Solid understanding of system design and scalability.
Product & Business
* Genuine curiosity about how users experience the product.
* Ability to translate design specs into actionable engineering tickets.
* Interest in understanding the why, not just the what .
AI
* Interest in AI for productivity (code generation, automation).
* Excitement about building AI features and infrastructure from scratch.
* Curiosity about emerging AI capabilities.
Communication
* Fluent in English (spoken and written). Spanish is a plus.
* Pragmatic problem-solver who balances speed and quality.
* Collaborative mindset with mentoring experience.
Bonus
* Experience in fintech, payments, or ecommerce.
Tech Stack
* Backend: Python, Django REST Framework
* Database: PostgreSQL
* Frontend: Angular / Vanilla JS
* Integrations: PHP (ecommerce plugins)
What the Company Offers
* Competitive compensation.
* Fully remote role (optional hub in Barcelona).
* Flexibility: 5-hour overlap with Spanish business hours (9–19 CET).
* High autonomy in both technical and product decisions.
* Opportunity to build AI infrastructure from zero.
* Growing team with strong technical leadership.