# Szymon Rybczak

> Szymon Rybczak is a teenage software engineer turned startup founder who became one of the youngest contributors to React Native at 16, maintained open-source libraries with millions of weekly downloads at Callstack, and got into Y Combinator (P26) while still in high school. He is now co-founder and CEO of TesterArmy, an AI QA agent that tests web and mobile apps in plain language, based in San Francisco.

- **Role:** Co-Founder & CEO at TesterArmy (YC P26)
- **Organizations:** TesterArmy, Callstack
- **From:** Poland
- **Nationality:** Polish
- **Education:** Was still in high school when accepted to Y Combinator, High school (Poland)
- **Known for:** One of the youngest contributors to React Native, at age 16, Maintained open-source libraries with 2M+ weekly downloads (React Native Community CLI, react-native-ai), Accepted into Y Combinator while still in high school

## Career timeline

- **~2020** — Started programming around age 14
- **2021** — First commercial development experience begins
- **~2021** — Became one of the youngest contributors to React Native at age 16
- **2023** — Gave first big-stage talk, 'Bringing React Server Components to React Native,' at React Day Berlin
- **2023** — Working as React Native Developer at Callstack, maintaining React Native Community CLI and react-native-ai
- **2024** — Talk 'Bringing AI to React Native' at thegeekconf
- **2025** — React Native AI talk at React Advanced London; got into Y Combinator while still in high school
- **2026** — Co-founder & CEO of TesterArmy (YC P26); relocated to San Francisco; launched AI QA agent

## Achievements

- One of the youngest contributors to React Native, at age 16
- Maintained open-source libraries with 2M+ weekly downloads (React Native Community CLI, react-native-ai)
- Accepted into Y Combinator while still in high school
- Co-founded TesterArmy, used in 20+ production companies at launch
- Youngest developer at Callstack
- Spoke at React Day Berlin, React Advanced London, and other major conferences

## Latest updates

- **2026-03** — TesterArmy raised a $130K seed round (Y Combinator P26)
- **2026-01** — Gave talk 'Building v0 iOS and Fixing React Native Along the Way' at React Universe On Air
- **2026-01** — Relocated to San Francisco to build TesterArmy full-time

## Links

- Website: https://szymonrybczak.dev
- LinkedIn: https://www.linkedin.com/in/szymonrybczak/
- Twitter/X: https://x.com/SzymonRybczak
- GitHub: https://github.com/szymonrybczak

---

Profile page: https://yespress.io/szymon-rybczak
Published by YesPress — https://yespress.io
Last updated: 2026-07-31