The Terrible Technical Architecture of my First Startup

A system that could only be built with the confidence of a 25-year-old Deloitte graduate with an AWS certification

Carbn defined my career.

For 2 years, I was the tech team of a tiny climate-action startup. I built a mobile app, and multiple backend architectures, from scratch, with close to zero experience.

When I started out my career at Deloitte, I was the classic case of the temporarily embarrassed young billionaire. Body buzzing with energy and undiagnosed ADHD, mind buzzing with dreams of greatness, yearning to someday do a startup. But, unlike my corporate colleagues, I had something my consulting companions didn’t have: I kept not getting promoted*.

*I was basically much too annoying to put in front of clients.

After the annual consulting tradition of “I’m leaving, for real-sies this time”, and some performative job applications to Revolut and Monzo, a recruiter got me in touch with something they thought would be right up my alley.

A commercial strategy consultant, with some cash, validated market research, and a dream, was searching for somebody with energy and a strong technical background to build an app in a potentially huge new market: Carbn.

Carbn was a gamified app that simplified climate action. Calculate your footprint, adapt your lifestyle, and pay for carbon offsets. It was peak late-2010s-ZIRP-era stuff. You honestly could not build this in 2025. But at the arse-end of the COVID lockdowns, the idea was catnip.

It was exactly what I’d daydreamed of for 4 years.

The founder and I immediately agreed to work together and became fast friends. I was the technical co-founding Camilla to a bootstrapping King Charles. I was offered generous double-digit equity, alongside a salary only slightly below what Deloitte paid their mid-level devs / janitors.

Today, I’m telling the story of the systems I created. The decisions I made as the tech cofounder to carry an app business, from scratch. We’ll look at:

• The initial, rudimentary, backend architecture our MVP shipped with.

• The “scalable” monstrosity I designed once we landed £200k in funding.

• What I should have done all along.

At no point did I know for sure what I was doing. But that’s part of the fun.

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I’ve recently created a new category of article to write about my rollercoaster of experience in and around startups: war stories. Contact me if you have a wild tech war story you’d love to share with the world!