Nothing is impossible, it can be just too expensive

I worked on

Ipla.tv: Largest Polish VOD platform. Optimize ruby code and maintain existing code base.
Roche Training Center: A platform with free training for doctors and pharmacists. Optimize database and add new features.
Siewert und Kau: Largest German electronics importing company with wholesalers IT system. Maintain, optimize and migrate to AWS.
FinalCAD: Construction Project Management Software. Maintain, optimize and development.
Neveo: Platform where you can send your photo and they will be printed as booklet and send to your elders. Huge database boost, fix image processing on web worker, generate PDF/X from HTML and support UTF-8.
JIRS: Small JIRA-like project written entirely in Rust. Both client side and backend side is written in Rust thanks to WASM. It's using WebSockets for communication and native CSS variables instead of any other precompiler so it's easy to check and fix. Maintainer.