Rebuilding a 6M+ user telco app
Lead engineer · a pan-European telco
I led the rebuild of the flagship app at a pan-European telco with 6M+ users. We moved it to a new platform with zero customer-facing downtime. The App Store rating went from 3.2 to 4.7 and cold start dropped from 5.6s to 0.5s. Along the way I grew mobile from a team of one to 12 engineers. Then I built a Travel eSIM product on my own, from idea to pitch to launch. It reached around 120,000 users in the UK and US within 6 months.
- Zero downtime
- 3.2 → 4.7 rating
- Team of 1 → 12
- Solo eSIM launch, ~120k users in 6 months









