Senior Backend Developer

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.

Do you have experience in Scalability?, 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)

• 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.

60.000€ - 80.000€

Remote