Carousell: Sell and Buy

Mobile Engineer

Firebase

React Native

Stripe

Carousell Mobile App Project Overview

Client: Carousell – A leading online marketplace for buying and selling secondhand goods across various categories, including fashion, electronics, cars, and home goods.

Objective: To create a seamless, user-friendly mobile app experience for buying and selling items. The app needed to cater to a large user base and support an intuitive interface for fast listings, browsing, and secure transactions.

My Role

Position: Senior Mobile Developer

Responsibilities:

Led the development of the Carousell mobile app using React Native, ensuring smooth functionality across both iOS and Android platforms.

Designed and implemented key features for the app, such as item listing, search functionality, chat between buyers and sellers, and secure payment options.

Collaborated closely with backend developers to integrate the app with Carousell's RESTful APIs, focusing on seamless user authentication, item management, and payment systems.

Ensured that the app provided smooth UI/UX for all users, with quick load times and an intuitive flow from listing to purchase.

Worked on enhancing notifications, including push notifications for new messages, item updates, and promotions, ensuring user engagement.

Key Achievements

Performance Improvements: Optimized app load times by 40% through code-splitting, lazy loading of images, and minimizing third-party libraries.

Enhanced User Engagement: Implemented an improved chat feature that allowed users to negotiate and arrange transactions within the app, leading to a 25% increase in interactions.

Secure Transactions: Integrated Stripe for secure payment processing, ensuring a safe and reliable transaction system for buyers and sellers.

Smooth User Experience: Successfully launched features like multi-item checkout and one-click payments, improving user retention by 30%.

Cross-Platform Compatibility: Ensured consistent app performance across iOS and Android devices, allowing a smooth and uniform experience for all users.

Technologies Used

Frontend: React Native, JavaScript, TypeScript, Redux for state management.

Backend Collaboration: Integrated with Carousell's existing APIs built using Node.js and Laravel for user management and transactions.

Payment Integration: Integrated Stripe API for secure payments and order tracking.

Push Notifications: Integrated Firebase Cloud Messaging (FCM) for real-time notifications.

Tools: Figma for UI/UX design, Git/GitHub for version control, Firebase for real-time data syncing.

Challenges and Solutions

Challenge 1: Ensuring fast item uploads and secure image processing.

Solution: Implemented image optimization and used cloud storage services for quick and secure uploading of product images.

Challenge 2: Handling large-scale data and real-time chat between users.

Solution: Utilized Firebase Realtime Database for efficient chat functionality and to handle large volumes of concurrent users.

Challenge 3: Providing cross-platform consistency between iOS and Android versions.

Solution: Used React Native’s cross-platform capabilities to maintain consistent performance while building platform-specific customizations where needed.

Conclusion

This project demonstrates my expertise in developing high-performance, feature-rich mobile applications using React Native. By focusing on user-centric design and secure, efficient functionality, I was able to help Carousell enhance its app and improve the buying and selling experience for users. I'm proud to have contributed to an app that is now integral to the way people in Singapore buy and sell their secondhand goods.