Hi There 👋
I'm Sief Ibrahim Ezzat
Backend-focused software engineer with strong experience in building secure, scalable systems using Clean Architecture, SOLID principles, and modern API design — mainly on ASP.NET Core, with Java/Spring Boot on the side.
About Me
Backend engineer who works daily across two stacks — .NET is my main weapon, and Java / Spring Boot is my second one. Same principles, two ecosystems.
.NET Primary
ASP.NET Core & C# — Clean Architecture, CQRS, EF Core, Identity, JWT auth and result patterns. This is where most of my shipped code lives.
Java Secondary
Spring Boot & Spring Security — REST services, RBAC, Redis slot-locking, Docker and CI. Same design thinking, different toolbox.
What I actually do
API design & REST
Versioned, well-shaped endpoints with predictable errors instead of surprises for whoever integrates next.
Data & persistence
Relational modelling, migrations and query tuning — schemas that stay easy to read and change as the app grows.
Auth & access control
JWT with refresh tokens, hashed credentials and role-based permissions — wired once, hard to break later.
Concurrency & correctness
Double-booking, slot races and lost updates — handled properly so two users can never claim the same thing twice.
Architecture
Clean / Onion layering, CQRS and SOLID — so the codebase stays testable when the team and the feature list grow.
Testing & delivery
Unit and integration tests that catch real bugs, plus Docker and CI so the same build runs everywhere.
Experience & Achievements
A snapshot of my journey in backend engineering and software development.
Services
What I can build for you, in plain terms.
APIs that don't break
REST APIs on ASP.NET Core with clean structure, so new features don't turn into spaghetti.
Login & permissions done right
JWT auth, refresh tokens, and role-based access — set up once, hard to break later.
No double-bookings
Handling concurrency properly, so two people can't grab the same slot at the same time.
Clean database design
EF Core / SQL Server schemas that stay easy to query and change as the app grows.
Architecture that scales
Clean Architecture and CQRS, so the codebase stays testable even as the team grows.
Actually tested code
Unit and integration tests that catch real bugs — not just coverage numbers.
Featured Projects
What I actually build — backend engines and full-stack systems.
Clinic Appointment System
Clinic booking platform on Clean Architecture and CQRS — JWT auth with refresh tokens, race-condition-safe double-booking prevention, Hangfire background jobs, domain events, audit trail and Serilog. The React client adds TanStack Query, Zustand and Zod-validated forms.
E_Commerce
Storefront plus REST API, built together. Onion Architecture backend with the Specification Pattern, JWT refresh tokens, Redis, Serilog, health checks, rate limiting and API versioning — consumed by a React 19 client with Zustand, Stripe payments and bilingual AR/EN support.
FlexCore — Gym Management
Gym management API and web client. JWT/RBAC, optimistic-locked class booking, transactional outbox with RabbitMQ event delivery, Redis caching and rate limiting, OpenTelemetry tracing, subscription freeze and family plans — with an Ant Design frontend on TanStack Query.
Let's Connect
Have an opportunity, a project in mind, or just want to chat? Reach out through any platform below.