About

I’m Mohamad Eldhemy, but most people call me Dhemy.

I’m a pragmatic backend engineer focused on modernizing complex systems, reducing technical debt, and improving reliability. I combine hands-on engineering with practical decisions that help teams deliver quickly while maintaining quality.

Much of my work has been shaped by my time at Reservix. I led technical direction for the Customer Data team, working with 4–6 engineers on systems serving roughly one million contacts. I helped redesign the MongoDB data model, removed an Elasticsearch scalability limit, and architected SyncHub, an event-driven synchronization platform built with Node.js, AWS Lambda, SNS, and SQS.

The technical work was only part of the job. I introduced testing infrastructure, improved CI feedback, expanded infrastructure as code, and mentored engineers through design discussions, architecture reviews, and code reviews. The goal was always the same: build reliable systems while helping the team make sound decisions independently.

Before Reservix, I spent six years at Twigano building products end to end. My work included PHP and Laravel APIs, subscription systems for the App Store and Google Play, Elasticsearch search, real-time chat, and a recommendation system using cosine similarity and Redis.

Open source

I maintain open-source packages for validating App Store and Google Play purchases and handling subscription lifecycles. Together, they have reached more than 3 million downloads: Laravel In-App Purchases, Google Play Billing, and App Store IAP.

I also built KoalaTs to understand the abstractions behind Node.js frameworks, then used it in OpenKairos to explore clean architecture and layering in practice.

Writing

I use this blog to share practical engineering notes from problems I encounter and approaches I test. I write about backend development, software design, testing, distributed systems, and the trade-offs behind maintainable software.

Connect

You can find me on LinkedIn, explore my work on GitHub, or reach me by email.