Rafael Roman

CTO & Co-founder at Upgrid — building the energy marketplace for Switzerland's local solar communities. 20+ years engineering critical infrastructure before becoming a founder.

Upgrid connects solar producers directly with their neighbors: lower prices, 100% local renewable energy, zero hardware. The energy grid is about to look very different.

Four years at N26 as Principal Engineer — payments architecture for millions of European customers, fraud prevention rebuilt end-to-end in six months. Then Principal Engineer at Personio. Before that: a decade delivering banking platforms across Europe at GFT, and three years at IBM's innovation lab.

Speaker: Kafka Summit London, KotlinConf, WeAreDevelopers World Congress, JavaCro, DevBCN, TEDx.

Based in Basel. From São Paulo. A decade in Barcelona.

Work

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May 2025 - Present

Upgrid

Co-founder & CTO

Building the technical foundation for local energy communities in Switzerland — a vZEV and LEG-compliant marketplace where solar producers sell directly to their neighbors. No hardware. No intermediaries. Lower bills, 100% local renewable energy. The mission: make community energy distribution as simple as a bank transfer.
Mar 2024 - May 2025

Personio

Principal Engineer

Platform engineering at one of Europe’s leading HR tech companies during a critical growth phase. Defined technical direction for core platform services, shaped engineering standards, and operated as a cross-team technical authority at scale.
Nov 2019 - Jan 2024

N26

Principal Engineer

Four years shaping the technical core of Europe’s most-funded neobank. As Principal Engineer: delivered the architectural vision for payments (bank and peer-to-peer transfers) and customer acquisition; led the overhaul of financial crime prevention — replaced a static rule engine spread across microservices with a real-time Apache Flink streaming system in under six months. Before that, as Tech Lead: architected the fee charging platform that became standard infrastructure embedded in N26’s ledger APIs across Europe.

Writing

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Sep 1, 2024
Rebuilding Fraud Prevention from Scratch in Six Months
How we replaced a static rule-based system spread across microservices with a real-time, Flink-driven risk engine at N26 — and what we learned.

#flink#distributed-systems#fintech#architecture#kotlin
Jul 2, 2024
Say Yes First
A product engineer brings a small tooling idea to platform. The default response — no, not now, here's why it won't work — builds a wall. There's a better one.

#engineering-leadership#company-culture#psychological-safety#platform-engineering
Feb 16, 2023
I Hardly Debug Anymore
I used to relaunch the app five times to check one change. TDD felt like homework until the feedback loop clicked — now tests are how I think, not what I do after.

#tdd#testing#engineering-leadership#code-quality

Connect

Interested in distributed systems, fintech, energy tech, or engineering leadership? Find me on: