I design systems
that scale & survive.
Production-grade Java & Spring Boot — event-driven microservices, secure REST APIs, and performance-critical data layers, operated end-to-end on my own infrastructure.
Selected work
AI Video Pipeline — Studio
Prompt → video. A multi-stage pipeline orchestrating Google Gemini (text → image → speech) with FFmpeg composition, self-hosted on a private VDS with a distributed render tier over Tailscale.
Vehicle Rental Platform
Event-driven Spring Boot microservices on Apache Kafka with PostgreSQL — the Outbox Pattern guarantees transactional consistency between database commits and event publication.
Mutfakkitap (GastroCost)
Recipe-costing & inventory SaaS — recursive sub-recipe costing, JWT API, Flutter frontend.
ULAŞIM Inventory App
Native Android stock-control used on the shop floor by manufacturing engineers, backed by Spring Boot APIs.
GPA Calculator
Fast public utility for computing grade point averages. Hosted on tunalime.dev/gpa.
Tools
A privacy-first toolbox — PDF, image & format converters, text utilities, and code/generators. Most run 100% in your browser (zero upload). tunalime.dev/tools.
Experience
- Built a Spring Boot backend and a Flutter cross-platform (mobile & web) frontend, delivering one consistent experience for restaurant operators across devices.
- Engineered recursive recipe-costing and sub-recipe algorithms, improving menu-pricing accuracy and eliminating manual calculation overhead for operators.
- Designed a referential-integrity-strict PostgreSQL schema for hierarchical menu and inventory data, exposed it through a JWT-secured REST API with role-based access, and shipped the stack as one-command Docker Compose deploys behind Nginx.
- Delivered a native Android (Java/Kotlin) inventory & stock-control app for ULAŞIM A.Ş., in production use by manufacturing engineers on the shop floor.
- Architected a vehicle rental & service platform as event-driven Spring Boot microservices on Kafka, applying the Outbox Pattern to guarantee transactional consistency between database writes and event publication.
- Built a multi-stage AI content pipeline hosted on tunalime.dev — Google Gemini (text → image → speech) orchestrated with FFmpeg video composition into an end-to-end automated workflow.
- Profiled hotspots and rewrote JPQL/SQL queries, cutting response times by up to 80% and significantly reducing database load in production.
- Designed and implemented features and business rules in Micronaut (Java/Kotlin) following SOLID, Clean Code and Hexagonal Architecture.
- Covered the work with JUnit 5 and Testcontainers unit/integration tests, ran rollback-safe data migrations, and reviewed peers’ changes via Gitflow.
Tech stack
JavaScript · SQL · PL/pgSQL
Micronaut · Hibernate/JPA
React · Flutter
Flutter (cross-platform)
Apache Kafka · RabbitMQ
Nginx · AWS EC2
Kubernetes · GitHub Actions
Clean · Hexagonal
DDD · SOLID · REST
JWT / OAuth
Testcontainers
Git / Gitflow
Peer code reviews
IntelliJ IDEA
About
I'm Mehmet Fethi Tunalı — a backend-focused engineer in İstanbul. I care about systems that stay correct and fast under real production load: clean boundaries, transactional integrity, data layers that hold.
I came to software from mechanical engineering at ITU, and it shows in how I work — I like understanding a system end-to-end and operating it myself, from Kafka topics down to the Nginx config and TLS certs.
Strong advocate of Clean Architecture, SOLID and DDD; currently pursuing an MSc in Computer Engineering.
Education
Certifications & Bootcamps
Languages
Let's build something
that holds up.
Open to backend & distributed-systems roles. Hiring for production-grade Java/Spring work? Reach out.