Hello, I'm

Mohammed Mostafa|

also known as elrefai

Software Engineer at Lesoll LogoLesoll
Based inCairo, Egypt
Get in TouchView Resume

About

I'm Mohammed Mostafa, a software engineer specializing in backend development, scalable APIs, payment integrations, and production systems with Node.js . I work across TypeScript, Express.js, MongoDB, PostgreSQL, Redis, Docker, and AWS, and I recently expanded into frontend development with Vue.js. As a backend developer, I built and shipped the systems behind production platforms like Lesoll logoLesoll and Egystay logo Egystay .

Turning ideas into real, functional systems is what drives me most. I'm passionate about building backend solutions, APIs, and tools that make life easier and boost productivity—whether for myself, my projects, or the developer community. You can explore my full list of projects .

Outside of coding, I enjoy photography and traveling. I'm also into anime, movies, and dramas, and I like to keep track of what I watch.

Mohammed Mostafa (elrefai99) GitHub contribution graph

Timeline

Lesoll logoLesoll

2023 - Present

Software Engineer

  • Built and operated the payment system integrating PayMob and Amazon Payment Services, processing ~10K transactions/month with HMAC-verified webhooks and idempotent handlers that guarantee zero double-charges.
  • Designed event-driven background processing (BullMQ + Redis) for email/SMS/OTP and notifications, moving ~500 jobs/day of slow third-party calls off the request path with automatic retries — removing external-provider latency and failures from user-facing endpoints.
  • Engineered a real-time chat and notifications layer (WebSockets / SSE) serving 5k concurrent users with reliable delivery.
  • Eliminated N+1 query patterns and refactored MongoDB aggregation pipelines, reducing key endpoint response times from 680 ms to 230 ms.
  • Built the CoHost system, cancellation policy, booking, reports, and employee tooling, plus a Puppeteer traffic-scraping pipeline used by 4k internal users.
  • Owned containerised deployment on AWS — Lesoll via Docker + EC2, EGYStay via Docker + EKS — with GitHub Actions CI/CD and Nginx, reducing deploy time to 1 minute.

Modern Academy (CS) logoModern Academy (CS)

2018 - 2022

B.S. Computer Science

Completed B.Sc. in Computing Web applications.

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2019 - Present

Founder

A freelance with my friend in academy