Hire the Best Kotlin Developers
in the United States
Mansfield, Texas
Top Rated Plus developer with a 100% Job Success Score specializing in high-performance Android (Kotlin/Jetpack Compose) and iOS (Swift/SwiftUI) applications. I provide a competitive edge by integrating on-device AI - from custom fine-tuned YOLO models for real-time detection to local LLM integration for intelligent UX. Simultaneously, I offer expert-level React Native development for clients seeking high-intensity, scalable cross-platform solutions. I bridge the gap between complex AI logic and polished mobile UX. A recent production success includes a YOLO-based scanning app achieving a 100% detection rate and 99% OCR accuracy via TensorFlow Lite. Technical Expertise: - On-Device AI & Vision: Expert in custom YOLO, OpenCV, and Google ML Kit for real-time scanning and on-device LLM features. - Native Excellence: Senior-level SwiftUI and Jetpack Compose development focusing on clean MVVM/MVI architecture. - High-Intensity React Native: Building robust cross-platform apps with seamless native-module integrations and high-performance UI. - Backend & Cloud: Scalable infrastructure using AWS Lambda, Firebase, Supabase, GraphQL, and REST APIs. - Growth & Revenue: Integration of MMPs (AppsFlyer, Adjust) and analytics (Mixpanel, Customerio) to track revenue and user behavior. - Modernization: Expert at migrating legacy codebases to modern frameworks and optimizing app performance. I lead projects from the first line of code to App Store/Google Play deployment, ensuring every app I ship is production-ready, performant, and data-informed.
- Kotlin
- React Native
- JetPack
- Java
- Swift
- SwiftUI
- Flutter
- RESTful API
- YOLO
- TensorFlow Lite
- PyTorch
- AWS Lambda
- Firebase
- GraphQL
- LLM Prompt Engineering
Townsend, Delaware
Top Rated Plus Full Stack Mobile App Developer | Top 3% UpWork Talent | Flutter | Kotlin | Swift | React, Node.js, AWS | Building Scalable Digital Experiences I’m a passionate and detail-oriented Full Stack Developer with over 10 years of experience crafting high-quality Web and Mobile applications for startups, enterprises, and agencies worldwide. I specialize in building end-to-end solutions using modern technologies and frameworks — from beautiful, responsive UIs to robust, scalable backend systems. 💡 Tech Stack Highlights: Frontend:Flutter (Dart), React-Native, Kotlin, Swift, React.js, Tailwind CSS, TypeScript Backend: Node.js (Next.js, NestJS), GraphQL, REST APIs Database:, MySQL, MSSQL, MongoDB, Firebase, Google Cloud DevOps/Cloud: Docker, GitHub Actions, AWS (EC2, S3, Lambda) Tools: Git, Jira, Notion, Postman, CI/CD, WebSockets, Stripe, OAuth2 What I Offer: Full-cycle Development from concept to Deployment Clean, maintainable, and scalable code Mobile-friendly, SEO-optimized, and fast-loading applications API integrations (Stripe, Twilio, Firebase, third-party REST/GraphQL) Agile collaboration with clear communication and on-time delivery I’ve completed a wide range of freelance projects: custom dashboards, SaaS platforms, eCommerce sites, API backends, mobile-first apps, and admin panels. Whether you're looking to launch an MVP, optimize an existing product, or scale your system, I bring technical expertise and business acumen. ✅ Why Clients Choose Me: Strong work ethic & attention to detail Fast learner and great problem solver Transparent and clear Communication Available for one-time projects or long-term collaboration Let’s build something amazing together. Drop me a message — I’d love to hear about your project!
- Kotlin
- Mobile App Development
- Flutter
- Dart
- Swift
- React Native
- React
- Node.js
- Next.js
- MongoDB
- Google Cloud Platform
- NestJS
- Firebase Cloud Firestore
- FlutterFlow
- .NET Core
- MySQL
- API Development
- Stripe API
- In-App Purchases
- In-App Subscription
Newburgh, New York
I am a seasoned Senior Full Stack Developer with over a decade of comprehensive experience in creating web and mobile applications and solutions. My expertise spans both frontend and backend technologies, enabling me to deliver robust and scalable applications tailored to business needs. I am now looking for a challenging role where I can apply my extensive hands-on experience and broad technical knowledge to drive innovation and excellence. I look forward to collaborating with you to create innovative solutions that meet your business objectives.
- Kotlin
- C#
- Python
- Amazon Web Services
- Azure DevOps
- ASP.NET
- Django
- HTML
- React
- Next.js
- Node.js
- Android App Development
- iOS Development
- Mobile App Development
- Swift
- React Native
- Flutter
- JavaScript
- Bluetooth LE
- Java
St. Louis, Missouri
I design and develop scalable, user-friendly web applications with a focus on innovation and efficiency. With a decade of experience, I excel in tackling complex coding challenges and managing multiple projects simultaneously. My strong foundation in software engineering is complemented by my passion for AI development, where I explore cutting-edge technologies to enhance user experiences. As a founder and lead developer, I have prioritized collaborative teamwork, mentoring fellow engineers, and fostering an environment that encourages creative problem-solving. If you're seeking a versatile developer who can deliver high-quality solutions while adapting to your unique project needs, let's connect and discuss how I can help bring your ideas to life.
- Web Development
- Product Development
- Web Application
- Artificial Intelligence
- Android App Development
- iOS Development
- App Development
- Mobile Game
- Python
- C#
- ASP.NET Core
- HTML
- Database
- Database Administration
- SwiftUI
Wilmington, Delaware
Did you know that 68% of MVPs fail within months of launch? Budgets blow up. Deadlines slip. Most teams lose focus on what actually matters. Sound familiar? I'm Herman, CEO of Coding House Studio. As your future technical partner and a mobile app development team, we help advertising agencies and small to mid-size businesses launch MVPs the right way — fast, focused, and without cutting corners. We build products ready to grow, centered on the features that matter most, and designed to get your idea in front of real users as quickly as possible. We reduce time to market by 40% compared to traditional alternatives by focusing strictly on high-impact MVP features. We've been doing this for over five years and we understand what our clients need, often before they say it. More than 20 projects delivered across North America. In Q1 of 2026, three of our clients went live on both the App Store and Google Play. We know what it takes to go from idea to launch as a mobile app developer — and we help you get there without wasting time or money. Our mobile app developer team of 15 handles everything from rough notes to a polished, ready-to-launch product. Most projects ship in 4 to 12 weeks, with ongoing support if you need it. We use AI to build faster and smarter — and help our clients integrate AI directly into their own apps. You get a clear path from idea to a working mobile app that launches, gets users, and scales. Instead of just development, you get a mobile app developer team focused on real outcomes for iOS and Android. If your mobile app developer process slows down or becomes too complex, you get structure and clarity. If you already have a mobile app, you get help with new features, API integration, and performance improvements. If you are starting from scratch, you get a clear path to MVP launch with an experienced mobile app developer by your side. Our clients rely on us for transparency. We help you figure out what your MVP needs right now — and what can wait. If you're looking for a trusted mobile app developer partner to launch on time and on budget, we're here. 𝗪𝗵𝗮𝘁 𝘆𝗼𝘂 𝗴𝗲𝘁 - Mobile app developer for iOS development and Android app development using Flutter, React Native, Swift, Kotlin, and Java, with strong focus on mobile app design, performance, and smartphone optimization - A clear MVP development process with fast time to market and structured app development - A full product built with backend systems, API integration, and scalable architecture using Node.js, JavaScript, Python, Firebase, and Supabase - Web application, admin dashboard, and user dashboard to support your product, built with a web developer approach using React and modern frontend tools, wordpress - Continuous product growth through mobile app improvement, mobile app redesign, and mobile app bug fix cycles You get experience from 20+ launched products across healthcare, SaaS platform, marketplaces, EdTech, and consumer apps. The focus is always the same. Your product works for real users, not just in code. 𝗪𝗵𝗮𝘁 𝗺𝗮𝗸𝗲𝘀 𝘁𝗵𝗲 𝗱𝗶𝗳𝗳𝗲𝗿𝗲𝗻𝗰𝗲 You get a product that performs after launch, not just something that was built. No unnecessary complexity and no overengineering. You get AI integration, payment integration, subscription system, and real-time communication only where it actually improves your product. 𝗥𝗲𝘀𝘂𝗹𝘁𝘀 𝘆𝗼𝘂 𝗰𝗮𝗻 𝗲𝘅𝗽𝗲𝗰𝘁 - 20+ mobile app developer projects launched across iOS and Android - Products with active users, subscription system, and real business logic built through mobile app developer - Scalable systems with API integration, admin dashboard, and user dashboard built from the start If you are looking for a mobile app developer who can take your idea to launch or move your product forward, send a message. You will get a clear breakdown of your idea and a step-by-step plan to launch your app faster. 𝘏𝘦𝘳𝘮𝘢𝘯 𝘒𝘳𝘢𝘷𝘤𝘩𝘦𝘯𝘬𝘰 𝘊𝘰𝘥𝘪𝘯𝘨𝘏𝘰𝘶𝘴𝘦𝘚𝘵𝘶𝘥𝘪𝘰 𝗠𝗲𝘀𝘀𝗮𝗴𝗲 𝗺𝗲 𝗮𝗻𝗱 𝗹𝗲𝘁’𝘀 𝘁𝗮𝗸𝗲 𝘆𝗼𝘂𝗿 𝗮𝗽𝗽 𝗶𝗱𝗲𝗮 𝗳𝗿𝗼𝗺 𝗰𝗼𝗻𝗰𝗲𝗽𝘁 𝘁𝗼 𝗹𝗮𝘂𝗻𝗰𝗵.
- Kotlin
- Mobile App Development
- Android
- Flutter
- iOS Development
- Android App Development
- Smartphone
- React Native
- Swift
- Mobile App
- JavaScript
- Hybrid App Development
- Mobile App Design
- App Development
- API Integration
- Node.js
- User Profile Creation
- Native App Development
- Mobile App Bug Fix
Phoenix, Arizona
Welcome to my Upwork profile! I specialize in building high-quality native iOS and Android applications (Swift | Kotlin), as well as cross-platform solutions using React Native, Flutter, and other popular frameworks. My expertise extends to all aspects of mobile app development, including UI/UX design, API integration, performance optimization, testing, and deployment. My top priority is to deliver high quality work that meets my clients' specific needs and requirements. Whether you need a brand new app built from scratch or an existing app revamped and updated, I can provide the expertise and skills needed to get the job done on time and within budget. Some of the services I offer include: Native iOS and Android app development (Swift - 5 years, Kotlin - 5 years, Java - 5 years) Cross-platform app development with React Native, Flutter, etc. (Flutter - 3+ years) Custom UI/UX design and development Integration of third-party APIs and services Performance optimization and app scaling Testing and debugging Deployment to app stores and ongoing maintenance and support. If you're looking for a reliable and experienced mobile developer who can deliver high-quality work on time and on budget, look no further. Let's discuss your project and see how I can help bring your vision to live!
- Kotlin
- Objective-C
- Swift
- React
- Flutter
- Android
- React Native
- GitHub
- Laravel
- GitLab
- Asana
- Kanban Board
- Scrum
- Version Control
- Jira
- Git
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