Backend Engineer

We are looking for a Backend Engineer to join a small, high-ownership engineering team working on new product initiatives. You will be primarily focused on new product initiatives, building new services and features, though you may occasionally need to navigate existing codebases. You use AI coding tools as a core part of how you work, and you are excited about what that unlocks. You will own backend architecture decisions and work closely with product and data to ship reliable, high-performance services at scale.

This is what you will do:

• Design, build and maintain backend services using Node.js
• Work with large-scale data systems, including ClickHouse and other relational and non-relational databases
• Build and maintain APIs that power our analytics product, working across real-time and historical datasets
• Ensure services are performant, scalable, and maintainable
• Contribute to architectural decisions for new product features
• Work in an Agile environment with short, focused sprints
• Collaborate closely with product, data and frontend teams

• 5+ years of experience building backend services in production environments
• Strong proficiency in Node.js and TypeScript
• Solid experience with relational and non-relational databases (MySQL, MongoDB, ClickHouse or similar columnar databases)
• Deep understanding of API design, data modeling, and web architecture
• Strong focus on performance: you think about query efficiency, latency and scale by default
• You use AI coding tools: Claude Code, Cursor, Copilot or similar, as a natural part of your development workflow, not as an afterthought
• Experience with CI/CD pipelines and cloud deployments (Docker, GitHub Actions, Jenkins or similar)
• You enjoy working on complex technical problems and take ownership of your solutions
• Familiar with testing practices including unit, integration and end-to-end testing

We will be impressed by experience in:

• Experience with ClickHouse or other OLAP / columnar databases
• Familiarity with real-time data pipelines or streaming data (Kafka, event ingestion APIs)
• Experience building data-intensive backend services at scale
• Experience designing or working with middleware layers: API gateways, request pipelines, data transformation services or similar
• Knowledge of PHP and/or Java/Spring
• Experience integrating AI tooling into development workflows in a meaningful way: using agents, MCP servers, or AI-assisted development at team level
• Active contributions to open-source projects

This will be you as part of the Marfeel team:

• Work on product that reaches publishers and newsrooms globally
• Option to work full remote, hybrid or office-based (if in BCN area)
• Support with home office equipment
• Flexible hours and early finish on Fridays
• Subsidized health insurance for you and your partner/family (Adeslas)
• Subsidized monthly plan to a large network of health and wellness centers (Wellhub)
• Transport, restaurant and kindergarten tickets (Cobee)
• Free language classes (English/Spanish)
• Open-space, light-filled and eco-conscious office with large sunny terrace (if BCN based)
• Unlimited refreshments including coffee, tea and soft drinks at the office (if BCN based)
• Loyalty vacation days
• Access to training platforms, courses and materials
• Referral bonus for talent brought to us by you

Our interview process:

• Phone call: covering the basics to make sure we are a good fit for each other
• Technical and personal interview: understanding you professionally and personally, and answering all your questions
• Test stage: a preview of the type of work, so you can see us in action too
• Test review interview: we discuss your test and provide feedback

Marfeel is a publishing platform that optimizes the traffic, performance, engagement, and monetization of the mobile experience. 850 publishers, including USAToday, Euronews, and El Confidencial use Marfeel to serve a billion mobile sessions, every month. We are constantly questioning how we can do things better and our goal is to continue to deliver beyond expectations.

We take a Technology-First approach and have a commitment to developing new tools for digital publishers to reach their audience. Our innovative technology, including PWAs, SEO and engagement tools, monetization and experimentation makes us proud of what we can offer to our clients: faster speeds, greater performance, and worldwide distribution.

Our team now has more than 170 members, made up of over 27 different nationalities. With headquarters in Barcelona and offices in New York and Bogotá, our people and our diversity are the reason behind our world-class product, and we’re still growing.