Romain Untereiner

Romain
Untereiner

Engineering leader / Entrepreneur / Lecturer

I build products, lead engineering teams, and teach. Based in Barcelona.

What I do

Services

01

Engineering Leadership

I embed with your team to define architecture, hire engineers, and ship products. From distributed systems to cloud infrastructure, I bring hands-on technical depth.

02

Technical Advisory

Due diligence, architecture reviews, and strategic guidance for founders and investors. I've audited startups for VCs and guided teams through Series A and acquisitions.

03

Teaching & Mentoring

I created the "Developer to CTO" module at Harbour.Space University. I teach engineers how to think beyond code: strategy, leadership, and building sustainable ventures.

04

Venture Building

From zero to acquisition. I co-founded Cantoo and took it to profitability in under two years. I help entrepreneurs validate, build, and scale their ideas.

Blog

Recent thoughts

View all

From Developer to CTO: What Nobody Tells You

The jump from writing code to leading a team requires a completely different set of skills. Here's what I teach my students at Harbour.Space about making that transition.

Read more: From Developer to CTO: What Nobody Tells You

Why Telecom Engineers Make Great CTOs

Distributed systems, real-time constraints, and regulatory compliance: the telecom background that shaped how I think about building products at scale.

Read more: Why Telecom Engineers Make Great CTOs

Let's build something together

Whether you need engineering leadership, technical advice, or a co-founder mindset, I'm always up for a good conversation.