Hire the Best Kotlin Developers
in Japan

Mobile & Web Developer | Automation & Integration I’m a developer with 4.5 years of experience in mobile app development and workflow automation. I help clients build reliable mobile solutions and streamline processes with Make.com integration. - Skilled in Android (Java, Kotlin) and iOS (Swift) - Automation and system integration with Make.com - Experience as a Bridge SE coordinating offshore teams - Focused on short-term, fully remote projects with clear communication Let’s work together to bring your ideas into reality.

Hi I am Edmer, I live in Shibuya, Tokyo, with around 10 years of IT experience as a web app and mobile app Engineer, I specialize in Typescript, Kotlin, Swift, Dart, Objective-C and Java Throughout my career, I’ve developed a strong track record in product design, implementation, integration testing, and bug fixing for Web, Android, iOS applications. I've had the opportunity to work on a variety of web and mobile applications, particularly in the E-COMMERCE space, including shopping carts and IoT applications. I’m passionate about creating user-friendly and innovative app solutions, and I’m excited to bring my expertise to new challenges. I have a Project Leader experience with my first IT company in Kawasaki, Kanagawa. I had experience making an app from scratch. I can help you build your app that will be modern, visually appealing and can be user friendly.

👋 Hello and welcome! I’m a passionate Senior Full-Stack Developer with 9+ years of experience, specializing in modern frontend & backend frameworks, AI, Web Scraping, Web3, and Mobile App Development. I don’t just write code—I craft high-performance, scalable, and future-ready solutions tailored to your unique needs. Whether you're a startup looking to disrupt the market or an established business aiming for digital transformation, I'm here to bring your vision to life. What I Can Do for You: ✅ Frontend Excellence: React.js, Next.js, Vue.js, Svelte, Angular, TypeScript, Tailwind CSS, Material-UI ✅ Backend Mastery: Node.js (Express/Nest.js), Python (Django/Flask), Laravel, Java Spring, .NET ✅ AI & Web3 Solutions: ChatGPT/OpenAI, TensorFlow, Blockchain, Smart Contracts, Solidity, NFT Platforms ✅ Web Scraping & Automation: Puppeteer, Selenium, Scrapy, BeautifulSoup, Reverse Engineering, Captcha Bypass ✅ Mobile App Development: React Native, Flutter, Swift, Kotlin, Expo – delivering seamless cross-platform experiences ✅ Database & API Integration: MySQL, PostgreSQL, MongoDB, Redis, Firebase, REST, GraphQL, Stripe, Twilio, Google Maps ✅ DevOps & Cloud: AWS, GCP, Docker, Kubernetes, CI/CD Pipelines Why Clients Love Working With Me: - 100% Client Satisfaction – I treat every project as my own and strive for perfection. - Fast & Reliable – Clear communication, quick execution, and on-time delivery. - Scalable & Secure Code – Best practices for performance optimization & cybersecurity. - Innovative Problem-Solver – I don’t just build software; I create solutions that drive success. - Long-Term Collaboration – I aim to build lasting relationships with my clients. Let’s build something amazing together! Message me now and let’s discuss how I can help you achieve your goals.

I build reliable backend systems, AI-enabled applications, and speech-processing pipelines using Python, FastAPI, SQL, AWS, and Docker. With over six years of professional software development experience, I can support a project from requirements and API design through implementation, testing, deployment, and maintenance. I can help you with: • Python and FastAPI backend development • REST API design, integration, and documentation • AI/ML service integration and data-processing pipelines • Speech AI systems, including ASR, TTS, and PyTorch-based workflows • Relational and time-series database design • AWS S3, Docker, Linux, Git, and deployment workflows • Integration with React, Next.js, Flutter, Kotlin, and mobile applications • Debugging, maintenance, and improvement of existing systems My professional experience includes: • Healthcare platforms for clinical video uploads, AI analysis, result management, and processing histories • A hospital-facing sleep-monitoring data management system • Healthcare mobile applications using Flutter, Health Connect, HealthKit, Unity, and iOS • A LINE bot supporting content submission, online payments, and administration • Speech-recognition and text-to-speech research involving Japanese-accented English and aviation communication I am currently pursuing a Ph.D. in Computer Science and Engineering at the University of Aizu. I have experience working with multinational teams and communicating with both technical and non-technical stakeholders in English, Japanese, and Mandarin Chinese. If you need a dependable engineer to build a new backend, integrate an AI service, or improve an existing application, feel free to send me a message.

Hi! My name is Kyo Yamamoto. I WORK WITH - Self-employed service providers - Business and enterprise companies EXPERINCE IN - Flutter Development (over 1.5year) - iOS Development (over 2.5 years) - Android Development (1 year) - Web Development (2.5 years) OTHER - Flutter Ninjas Speaker 2025

The hard part of shipping a SaaS isn't writing code — it's keeping iOS, Android, and Rails coherent across years of iteration. That's where I work. I'm a full-stack mobile engineer who designs, ships, and operates iOS (Swift / SwiftUI / SwiftData), Android (Kotlin / Jetpack Compose), and Ruby on Rails — all three layers — as a single developer. I've been writing code professionally for 20+ years and shipping to the App Store and Google Play for over a decade. Since 2025 my focus has been AI-driven development with Claude Code and the Claude Agent SDK. Recent independent work: • Printora — iOS app that auto-detects people in photos and arranges them into A4-optimized print layouts. Swift / SwiftUI / SwiftData / Vision Framework. 491 unit tests with Swift Testing. RevenueCat freemium. On the App Store. • My Texas Method — Strength-training program generator based on the Texas Method. Swift 6, Swift Charts, SwiftData, and an Apple Watch companion via WatchConnectivity. 973 unit tests. Ranked #23 on Product Hunt's daily leaderboard (74 upvotes). • nativeapptemplateapi — Rails 8.1 multi-tenant SaaS API using Solid Queue / Cable / Cache (no external Redis), acts_as_tenant, devise_token_auth, pundit. Listed on Awesome Rails. • nativeapptemplate-agent — Claude Agent SDK CLI (Node 22 + TypeScript) that scaffolds iOS / Android / Rails projects with a multi-agent pipeline (Planner / Workers / Reviewer / Judge), Opus 4.7 vision-model UI scoring, and mobile-mcp UI automation. Built at Cerebral Valley's "Built with Opus 4.7" hackathon and published to npm. • NativeAppTemplate-Free-iOS — open-source modern app template with auth + NFC. 98★ on GitHub. Contract highlight: an XCFramework that reads Japanese Residence Cards (在留カード) over NFC, based on the Ministry of Justice public spec, validated with real test cards at the Immigration Services Agency, 96% unit-test coverage. Strengths: shipping mobile + backend single-handedly, taking products all the way from concept to App Store / Product Hunt / npm / OSS, and applying agent-based workflows to real shipping products. Stack: Swift / SwiftUI / Kotlin / Jetpack Compose / Ruby on Rails / Hotwire / Tailwind CSS / TypeScript I'm actively open to new opportunities — full-time, contract, or interesting collaborations. I prefer environments where I can use Claude Code as my coding assistant.