Open to opportunities

Kiên Nguyễn

@kinnguyn

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React Native developer who builds high-performance cross-platform apps with strong Java backend insight.

Vietnam

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What I'm looking for

I’m looking for a team where I can own end-to-end React Native delivery, optimize performance and stability, and partner tightly with backend/design. I want to keep code clean and ship user-impacting mobile experiences in real domains like food delivery and education.

I’m a React Native developer with 5 years of experience in software engineering, specializing in building high-performance cross-platform applications for iOS and Android. I bring a strong Java backend background (2 years) that helps me design robust client-side architectures, optimize API integrations, and handle complex data synchronization.

I’ve owned the full mobile development lifecycle—implementing pixel-perfect UI/UX, managing complex state, and successfully deploying apps on App Store and Google Play. I’m passionate about clean code, performance optimization, and using modern mobile technologies to deliver impactful user experiences, especially in Food delivery and Education domains.

In my current roles, I focus on stability and speed: I proactively identify bottlenecks like slow rendering and memory leaks (e.g., FlashList and memoization), and I monitor production health through Crashlytics to maintain a 99.9% crash-free session rate. I also refactor legacy modules to reduce technical debt and improve long-term maintainability.

I collaborate closely with backend, design, and testing teams to troubleshoot integration issues and ensure high-quality releases. Whether I’m integrating real-time features (Socket.IO), handling background location updates, or implementing secure authentication (Firebase Auth, JWT token management), I aim to deliver reliable, user-first mobile products.

Experience

Work history, roles, and key accomplishments

Current

Mobile Developer

Current

Just.engineer

Sep 2024 - Present (1 year 9 months)

Owned end-to-end development for an on-demand food/pharmacy/supermarket delivery app, from environment setup to releasing updates on App Store and Google Play. Improved performance to maintain smooth 60fps and achieved a 99.9% crash-free session rate using Crashlytics.

React Native TypeScript Redux toolkit Zustand FlashList Performance Optimization Firebase Crashlytics Mapbox

Current

Go Mobile Developer

Current

Just.engineer

Aug 2023 - Present (2 years 10 months)

Built driver-facing features for an order-assignment and earnings tracking app, based on business requirements. Integrated Socket.IO for real-time order notifications and implemented background location updates to synchronize driver coordinates to the server.

React Native TypeScript Zustand Socket.IO Background Location Updates Mapbox State Management CodePush API Integration

Current

Store Mobile Developer

Current

Just.engineer

Feb 2023 - Present (3 years 4 months)

Developed the merchant/restaurant owner mobile app for managing status, orders, menus, and statistics within the Locate system. Implemented reliable order syncing via polling, optimized performance to reduce memory leaks, and handled complex accept/reject logic to trigger driver dispatch.

React Native TypeScript Zustand Polling Strategy Performance Optimization Order State Logic CodePush State Management

OJT Management System Developer

Fpt University

Oct 2022 - Jan 2023 (3 months)

Developed an OJT Management System to replace manual workflows for students and staff, including CV submission, proposals, activity tracking, and enterprise/alumni operations. Managed requirements communication, implemented features with UI/UX design, and supported debugging and bug fixing while maintaining SRS and design documents.

jQuery UI UX Design SRS Documentation Requirements Gathering Debugging Code Review System Integration

Back-End Developer

Vmo Holdings

Jun 2021 - Sep 2022 (1 year 3 months)

Contributed to the development and maintenance of a long-running bicycle marketplace platform, implementing modules and fixing bugs. Improved backend performance using Java/Spring Boot and supported teammates while reporting progress to managers.

Java Spring Boot JPA Modules API Support Maintenance Engineering