Netenders is an international e-commerce group based in Barcelona, operating several leading online stores in Europe and North America. As we continue to grow and innovate, we are developing our own cutting-edge e-commerce Content Management System (CMS) to revolutionize the online shopping experience across our brands. We are looking for a Senior Full Stack Developer (Freelance) to collaborate with our in-house tech team on high-impact, long-term projects.

This is a freelance position, with adaptable remote work (Barcelona-based candidates are a plus).

Your Role

Leading the technical evolution and optimization of our multi-brand e-commerce ecosystem.

Architecting scalable React frontends and robust Ruby on Rails backend services.

Developing core CMS features, specifically focusing on complex supplier integrations and high-volume data flows.

Designing high-performance APIs and back-office tools for pricing and SEO management.

Ensuring code quality and architectural consistency through expert-level pull request reviews.

Collaborating with cross-functional teams to translate business requirements into clean, maintainable code.

About you

You are a self-driven developer with a consultant mindset.



You don’t just write code; you design solutions that consider the long-term health of the product. You enjoy the autonomy of freelance work but understand the importance of mentorship and sharing your technical expertise to help internal teams grow.

Requirements

5+ years of experience with Ruby on Rails (v5+), including successful version migrations.

3+ years of professional experience building modern interfaces with React.

Deep understanding of software design patterns and RESTful API architecture.

Proven track record in e-commerce or handling complex, data-heavy backend systems.

Strong proficiency with Docker and GIT-based workflows.

Ability to work autonomously and communicate complex technical concepts clearly.

Nice-to-have: Experience with Hotwire Native, ElasticSearch, Redis, or Google Cloud Platform.

We celebrate diversity and want our team to reflect this inclusively. At Netenders , we are committed to equal employment opportunities regardless of ethnicity, religion, gender, national origin, sexual orientation, age, marital status, disability, gender, gender identity, or gender expression

📌 Senior Full Stack Developer - Freelancer (Madrid)
🏢 Netenders
📍 Madrid