About

Hi, I’m Bartosz Jedrzejewski

I’m an Engineering Manager at Meta’s Superintelligence Labs in London, where I lead teams building the data infrastructure that powers Meta’s generative AI - web crawlers, synthetic data pipelines, and infrastructure for AI agents.

Before moving into management, I spent a decade as a software engineer across fintech, consulting, and big tech - from building financial risk systems at Lombard Risk, to Technical Principal at Scott Logic, to scaling ads infrastructure at Meta.

I studied Mathematical Science at City University London and Computer Science at the University of Oxford, where I also played chess competitively. Before that, I was a finalist in the Polish Mathematical Olympiad - a formative experience that shaped how I think about problems.

About this blog

e4developer is where I share my open and honest views on software development, technology, and working with people. The name - e4 - comes from a chess move. It’s how I start most of my games.

This blog started in 2017 as a place to explore microservices, Java, and Spring Boot. Over the years it grew to cover software architecture, DevOps, AWS, and tech leadership. Now, as AI reshapes how we build software, I’m expanding into AI/LLM systems, distributed infrastructure, and engineering management - the things I work on every day.

I’ve written over 150 posts here. Some of the most popular ones - like HATEOAS - a simple explanation , Spring Boot Best Practices , and Please, stop writing so many for loops in Java! - continue to help developers years after they were published.

Other things I build

The Dice Drop - Board game media platform covering board games, crowdfunding campaigns, and the tabletop hobby
BattleCast - D&D 5e combat simulator with grid-based battles and Monte Carlo probability analysis
LiveRail London - iOS app for fast London journey planning with real-time train status
Chess Spark Miner - Open-source tool for analysing Lichess datasets with Apache Spark