Leo Gisselberg.

Copper builds software for institutional investors in crypto: web3 wallets, trading terminals, and dashboards. I maintain and evolve that whole ecosystem of applications.

I lead the frontend side of feature development across internal and customer facing products. When AI entered the workflow I helped define how we use it: new workflows, tooling for automation, and quality standards for the output.

One of Sweden's first dark kitchen startups. As an early employee I helped define the foundations for the frontend applications and how the teams worked.

I built user facing and internal products, plus shared internal tooling: a reusable design system and shared packages. I also onboarded and trained junior developers. Everything had to be built with scale in mind, which pushed me hard on performance.

PMG runs Europe's biggest pet marketplaces, including Pets4Homes in the UK and Hästnet in Sweden, with millions of monthly users.

I helped build the new scalable platform meant to replace the old outdated sites: fresher UI, updated features, built to handle marketplace-level traffic.

Early employee at what became Europe's leading shared micromobility company. The pace meant I did what most people do in three or four years in under two.

I built internal applications used daily by over 500 employees: new features, performance work, bug hunts, and new engineering guidelines for the codebase.

Built an in-house recruitment and consultant management system, with shorter consulting gigs at other companies on the side.

Where it started. WordPress themes, PHP, jQuery, and the first React work. Internship to full time in three months.