Senior Backend Engineer
Hilmi Cihan Yıldırım
Specializing in high-performance .NET Core microservices, legacy system modernization, and scalable API architecture. My deep backend expertise is backed by a full-stack product mindset, proven by single-handedly deploying 6 live App Store applications and 4 web platforms using AI-accelerated workflows.
Experience
ARC Europe ↗
Belgium
- Architected the modernization of a 15-year-old legacy application, turning outdated workflows into a high-performance .NET Core system.
- Boosted API performance 2–3× with EF Core query optimization and a distributed Redis caching layer.
- Engineered automated background processing with Hangfire, removing manual bottlenecks and improving reliability.
- Accelerated frontend modernization with AI-assisted development (Claude), redesigning and shipping updated UI components fast.
Service Management Group ↗
USA
- Engineered and maintained 10+ .NET Core 6+ microservices at enterprise scale, processing over 600 million transactions a day.
- Accelerated transaction processing 40% through backend optimization and system tuning.
- Cut deployment times 50% by architecting and automating CI/CD pipelines on GitHub Actions and Azure DevOps.
- Mentored two mid-level engineers on backend architecture and coding practices, lifting team output.
StartupHeroes · Gopuff ↗
İstanbul
- Engineered cross-platform mobile features in Flutter and Node.js microservices, driving a 25% increase in active user engagement.
- Optimized checkout and payment integration flows, lifting transaction success rates 15% and reducing payment drop-offs.
- Implemented a targeted push notification architecture for real-time order updates and retention campaigns.
Keepnet Labs ↗
London
- Drove the acquisition of top-tier banking clients by building complex IBM X-Force and Fortinet integrations that extended the platform's security capabilities.
- Cut API response times 35% through .NET Core 3.1 optimization and system refactoring.
Stack
Apps I built and shipped alone
App Store apps — built, deployed and maintained end to end. React Native, Expo, RevenueCat.
ALL APPS ON THE APP STORE ↗
Planix
Plans and schedules social posts across platforms.
DueMind
Tracks recurring bills, reminds before due dates.
DoseMind
Medication reminders and dose tracking.
FreeHesapla
Everyday calculators — loans, unit conversion.
NoCook
No-cook recipes for meals under ten minutes.
SuppTrack
Tracks daily supplements and intake streaks.
I teach this, too
Udemy instructor since 2023 — 40+ hours of content on GitHub Actions, design patterns and EF Core, taught to engineers in more than 100 countries.
Education & awards
Middle East Technical University
B.S. Computer Engineering, 2016–2021, Ankara. CGPA 8+/10, graduated with honors.
Top 0.01% nationally
University entrance exam, out of roughly two million candidates.
Mask Detection · national award
Senior project, 2020–21. Flutter + Flask with a DSDF model detecting masks from public camera feeds. Backed by ASELSAN.
Let's build something fast.
Open to senior backend roles and contract work — remote or hybrid. Usually replying within a day.