Backend Software Engineer

About the Position

Backend Software Engineer

We are looking for a Mid-Level Backend Software Engineer to join our Tech Team at Flanks, a fast-growing fintech startup based in Barcelona. If you are passionate about designing and optimizing data pipelines and backend services, this role is for you.

About the Role

As a Mid-Level Backend Engineer, you will be responsible for designing, building, and optimizing the data pipelines and backend services that ensure clean, reliable data flows across our organization. You will own the full lifecycle of data ingestion and transformation, from understanding business requirements to production deployment, and directly shape the backend infrastructure that powers our data-driven decision-making.

Responsibilities

• Design, develop, and maintain scalable ETL/ELT pipelines to ingest, transform, and load data from multiple sources into our core systems.
• Write clean, efficient Python code with a strong focus on performance, applying optimal data structures and algorithms to handle high-volume datasets reliably.
• Collaborate on database schema design (SQL and NoSQL) and own query performance optimization to ensure fast, accurate data access.
• Implement unit tests, integration tests, and data quality checks to guarantee pipeline integrity and catch issues before they reach production.
• Deploy and iterate on pipelines using CI/CD practices and containerization tools such as Docker, participating actively in code reviews to uphold team standards.

Requirements

• Strong Python and/or JavaScript engineering skills, with a focus on performance, memory efficiency, and writing maintainable, production-grade code.
• Solid experience building and operating data pipelines - ETL/ELT patterns, pipeline orchestration, and handling large-scale data ingestion - or experience building backend services for a product, ideally with exposure to Elasticsearch.
• Familiarity with both SQL and NoSQL databases, including schema design and query optimization.
• Comfort working autonomously - able to take a high-level requirement, define scope, and drive it to production without heavy hand-holding.
• Ability to navigate unfamiliar codebases quickly and contribute meaningfully from an early stage.
• Experience with CI/CD workflows and containerization (Docker or similar).
• Willingness to understand the financial data we work with and the formulas you will be responsible for implementing. It is important to be curious and open to learning how financial markets work, as this context is essential to correctly ingest, process, and expose financial data.
• Language Proficiency: Professional proficiency in both English and Spanish to collaborate effectively in our bilingual environment.

We Offer

• A full-time, permanent contract.
• A salary range of €35,000 – €50,000 gross per year, based on experience.
• A cool office between Sants Estació and Plaça Espanya with stunning views of Barcelona.
• Flexible working hours and hybrid work options.
• Paid day off on your birthday.
• Weekly fresh fruit, coffee, and tea on tap.
• Friday happy hours after our all-hands meetings (totally optional, of course!).
• Team-building events to bond and have fun.
• Health insurance and flexible compensation with Alan.
• A digital canteen, thanks to Kombo, subsidized at 50%.
• A yearly training budget to keep growing.

About the Company

Flanks

Redefining the wealth management industry to make it simpler, seamless, and accessible to more people. Founded in 2019 and based in Barcelona, we've brought together a team of passionate wealth management and tech pros, all with a shared goal: to change how wealth management is done. Backed by €23 million in investment, we're growing fast, and we're not stopping anytime soon!

What we stand for:

• People First 🤝 – our team comes first. We want every Flanker to feel at home, engaged, and part of something bigger.
• Keep Growing 🌱 – as the company grows, so should you. We're all about personal and professional development here.
• Think Twice, Act Once 🧠💭 – we believe in thoughtful decisions, considering the impact on both our team and our clients before taking action.

If you're looking for a place where you can grow and make an impact at a fast-paced, exciting fintech startup, this might just be the place for you! 🎯✨

At Flanks, we believe in fostering diversity and inclusion across everything we do. We're proud to be an equal opportunity employer, and we welcome all applications regardless of race, religion, gender, age, or disability status. Additionally, we have an Equality Plan in place to ensure fairness and inclusivity in all our policies and practices. 🌈💼