Blog — Mohamed ErfanWriting on backend engineering, distributed systems, and lessons from production.https://mderfan.com/Building a Personal Expense Tracker with Next.js 15, Prisma, and Offline-First Synchttps://mderfan.com/blog/finance-tracker/https://mderfan.com/blog/finance-tracker/Notes on building a personal finance app — natural language input, offline-first IndexedDB sync, recurring transactions, and visual regression testing.Tue, 28 Apr 2026 00:00:00 GMTHello, Worldhttps://mderfan.com/blog/hello-world/https://mderfan.com/blog/hello-world/First post — a brief note on why I started writing.Fri, 24 Apr 2026 00:00:00 GMT