Fernando Pradas

Hi, I'm

Fernando Pradas.

I'm a backend engineer based in Barcelona. Over the last 12 years I've built distributed systems at very different scales, from early-stage products to platforms with 50-100M monthly active users and 5K-50K RPS.

About Me

I'm a backend engineer with over 12 years building distributed systems across different scales and domains. I've worked on authentication infrastructure for 700K daily active users at letgo, led the backend chapter at OLX Autos through a microservices-to-EDA transition, and taught backend frameworks at postgraduate level at La Salle BCN.

Right now I'm at AUTO1 Group, working on the systems that power their used car marketplace across 30+ European countries.

Outside of work I follow the blockchain space, tinker with Go side projects, and watch too much football.

Use the right tool for the job, not the fashionable one
Iterate first, optimise when you have evidence
Reliability is built, not assumed
Nothing ships without the team

Technologies I work with

Kotlin Go Java Kafka Spring Boot Kubernetes Docker PostgreSQL Symfony Event-Driven Architecture Microservices DDD

Experience

Senior Software Engineer

AUTO1 Group

Apr 2025 – Present

Remote

Europe's leading digital automotive platform, operating in 30+ countries with revenues of ~€6.3B (2024).

  • Building reliable and scalable systems to consolidate AUTO1's presence across Europe.

Backend Chapter Lead

OLX Autos

Jul 2022 – Aug 2023

Led the evolution of OLX Autos' backend architecture, spearheading the transition from microservices to a fully Event-Driven Architecture. Worked cross-functionally with 4 teams.

  • Defined Kafka-based EDA best practices, reducing response time by 40%.
  • Standardized GitLab CI/CD pipelines, cutting deployment time by 35% and raising success rate to 98%.
  • Integrated SonarQube: improved code coverage by 25% and reduced critical vulnerabilities by 80% in 6 months.

Senior Software Engineer

OLX Autos

Jan 2022 – Aug 2023

1 year 8 months total at OLX Autos

Helped OLX Autos grow and consolidate in LATAM and other key markets (500K+ cars listed/month, 50K+ inspections).

  • Led full data migration from the legacy platform to the OLX platform.
  • Refactored legacy Java code to Kotlin, integrating unit and integration tests.
  • Implemented anti-corruption layer pattern to build new features with Kotlin + Spring Boot.

Teacher

La Salle BCN

Feb 2020 – Jan 2022

Barcelona

Faculty member in the Master's program for High-Performance Web Programming at La Salle (Ramon Llull University), specializing in Development Frameworks.

  • Taught Symfony, dependency injection, ORM, and Domain-Driven Design (DDD) principles with a hands-on approach.
  • Achieved a 4.9/5 rating in anonymous teacher evaluations.

Senior Software Engineer

letgo

Jan 2018 – Dec 2021

Barcelona

First Spanish startup to achieve unicorn status ($1B+ valuation), with 100M+ downloads and 20M+ monthly active users. Part of the user-focused and authentication team for ~700K daily active users.

  • Built Trust & Safety tooling to mitigate and prevent scams at scale.
  • Collaborated with SecOps to enhance platform security and mitigate external attacks.
  • Maintained User microservices with SLA consistently above 99.99%.

Co-founder & Ethereum Blockchain Engineer

Autónomo

Jan 2017 – Sep 2018

Co-founded a collaborative crypto platform focused on ICO analysis with community reward mechanics via utility tokens.

  • Designed smart contracts in Solidity (ERC-20, Crowdsale, Airdrop) following OpenZeppelin security standards.
  • Deployed Gnosis multi-signature wallet on testnet and mainnet via Infura API.
  • Successfully deployed all contracts to Ethereum mainnet and launched the ICO in 2018.

Senior Software Engineer

Atrápalo

Nov 2015 – Jan 2018

Barcelona

Spain's leading travel and leisure platform with significant presence in LATAM. Worked on the ticketing vertical (Atrápalo Eventos).

  • Designed services to sell and manage ticket stock for events and activities.
  • Led migration from monolithic PHP to microservices in Symfony, guided by DDD under CTO Carlos Buenosvinos.

Full Stack Developer

BAB.

Dec 2012 – Nov 2015

Barcelona

Small dynamic company (12-14 employees) focused on SaaS CMS/e-commerce solutions and custom client projects.

  • Built MOOC platform (Homuork) and online magazine kiosk (iQUIOSC.cat).
  • Contributed to the initial design and conceptualization of CMS platform (comitium.io).

Education

2008 – 2012

Technical Engineering, Computer Systems

Universitat Autònoma de Barcelona

Get In Touch

If you want to talk about distributed systems, a collaboration, or anything else, find me on LinkedIn.

Connect on LinkedIn