Currently buildingEvent technology systems

Full-stack Software Developer

I build product-driven mobile and web applications. Product builder

Fast, reliable, and scalable digital experiences.

.NETReact NativeTypeScriptAPI-firstMobile-first
Umut Öztosun

About

I am a product-focused full-stack software developer building modern web, mobile, and backend solutions. I work with C#, .NET, ASP.NET MVC, React Native, Expo, JavaScript, TypeScript, Python, SQL, MSSQL, SQLite, Entity Framework, REST API integrations, Supabase, Git, HTML, CSS, Bootstrap, and modern application architectures. I develop end-to-end solutions across a wide range of needs, from mobile applications and custom business software to admin panels and MVP products. When building software, I always prioritize performance, maintainability, scalability, security, and user experience. My goal is not only to create systems that work, but to build digital products that feel reliable, are ready to grow, and create real business value. By combining technical expertise with fast problem-solving, product thinking, and a modern UI mindset, I turn early-stage ideas into polished, impactful, and effective software experiences. I also work on automation flows, data-driven processes, and systems that improve operational efficiency. I enjoy building solutions that reduce repetitive work, accelerate workflows, and help teams operate more effectively. For me, software is not just about writing code — it is about understanding needs clearly and transforming them into strong, sustainable, and valuable products.

Core focus

Product-focused full-stack software developer building modern web, mobile, and backend solutions.

Strengths

MobileBackendProductAutomationIntegrationScalability

Technology stack

Frontend & UI

HTMLCSSBootstrapJavaScriptTypeScriptReactNext.jsTailwind CSS

Mobile

React NativeExpoMobile-first UXStore release workflows

Backend & API

C#.NETASP.NET MVCREST APIPythonEntity FrameworkService design

Databases & data

SQL Server (MSSQL)SQLitePostgreSQLRedisSQLData modeling

Cloud / DevOps

DockerSupabaseVercelCloudflareDeployment & hosting

Tools & workflow

GitGitHubPostmanFigmaCI/CD fundamentals

Architecture & security

Secure API designAuthentication & authorizationInput validationOWASP awarenessResilient architecture

Mobile app showcase

Featured app

Hedefe Koş!

Backend-supported mobile game experience built around decision making, risk management, and progression systems.

React NativeExpoTypeScriptSupabase
Hedefe Koş! preview
Hedefe Koş!Live

Hedefe Koş!

Backend-supported mobile game experience built around decision making, risk management, and progression systems.

React NativeExpoTypeScript
View details
Billionaire's ChatLive

Billionaire's Chat

Modern social chat app built around community, visibility, and credit-based mechanics.

React NativeExpoTypeScript
View details
SignalistLive

Signalist

Mobile application developed for learning and translating Morse code.

React NativeExpoTypeScript
View details
Hook QRIn progress

Hook QR

Mobile QR scanning app built for fast event check-in, validation, and field operations.

React NativeExpoJavaScript
View details
ChronoSnapsPrototype

ChronoSnaps

Content project focused on producing daily history content in short-form video format.

Next.jsAutomationContent Pipeline
Website coming soon
View details

Selected projects

Event Control Center

2024

Centralized control system for managing large-scale event operations from a single panel.

Challenge

Handling high traffic, role-based authorization, and real-time data tracking.

Outcome

Operational processes became faster and error rates dropped noticeably.

Next.js.NETSQL ServerRedis

QR Event Check-in System

2024

Mobile event system enabling fast check-in and check-out via QR codes.

Challenge

Offline support, fast scanning, and reliable data synchronization.

Outcome

Queue times decreased and field operations became more efficient.

React NativeExpo.NETSQLite

Offline-first Mobile Queue

2024

Architecture that stores data locally when offline and syncs automatically when back online.

Challenge

Resolving data conflicts, ensuring integrity, and maintaining performance.

Outcome

Data loss was prevented and field teams could operate without interruption.

React NativeExpoSQLiteTypeScript

Event Registration Platform

2023

Web-based platform that digitizes attendee registration and management processes.

Challenge

Handling large datasets with fast filtering and search capabilities.

Outcome

Manual processes decreased and management became faster.

.NET MVCSQL ServerjQueryBootstrap

API Integration Layer

2023

Integration layer managing data exchange between systems.

Challenge

Error handling, retry mechanisms, and logging processes.

Outcome

Data flow between systems became more stable and errors decreased.

Node.jsTypeScriptRESTDocker

Admin Reporting Dashboard

2023

Admin dashboard providing reporting and analytics.

Challenge

High-performance queries on large datasets.

Outcome

Reporting became faster and decision-making improved.

Next.js.NETSQL Server

Notification System

2024

Centralized system for managing push, email, and system notifications.

Challenge

Notification ordering, failed deliveries, and retry handling.

Outcome

Delivery success rate increased and the system became more reliable.

Node.jsFirebaseRedis

Digital Badge System

2023

QR-based digital badge system for secure event access control.

Challenge

Security, fraud prevention, and fast validation.

Outcome

Unauthorized access was reduced and entry processes became faster.

React Native.NETPostgreSQL

Experience

2022 - Present

Full-stack & Mobile Software Developer

Building end-to-end solutions across event technologies, mobile applications, and API-driven systems.

  • Analyze business requirements and design scalable technical architectures
  • Lead end-to-end development of mobile apps (React Native / Expo) and backend systems (.NET, Node.js)
  • Build offline-first architectures and reliable data synchronization systems
  • Design and implement QR-based check-in and validation systems
  • Optimize performance and scalability for high-traffic systems
  • Develop REST APIs and integration services across multiple systems
  • Design databases, optimize queries, and ensure data integrity
  • Implement real-time data processing and reporting systems
  • Ensure high code quality, security, and maintainability
  • Build modern, mobile-first, user-centric interfaces

Services

Building scalable custom software solutions for enterprise and vertical needs
Developing high-performance mobile apps for iOS and Android using React Native (Expo)
Designing modern, secure, and scalable backend & API architectures with .NET and Node.js
Developing event registration, QR-based check-in/out, and field operation systems
Building offline-first mobile systems and reliable data synchronization infrastructures
Creating admin panels, dashboards, and internal operational tools
Building MVPs and taking products from idea to production
Integrating third-party services such as payments, notifications, and authentication
Building real-time data pipelines, reporting systems, and operational automation
Optimizing performance, improving security, and ensuring maintainable software
Providing technical consulting, system design, and architecture roadmaps

Contact

Complete the security check before sending.

Built with precision — Umut Öztosun