Oscar Yuandinata, Developer in Tokyo, Japan
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Oscar Yuandinata

Verified Expert  in Engineering

Software Developer

Location
Tokyo, Japan
Toptal Member Since
October 20, 2022

Oscar is a senior software engineer with over a decade of experience building APIs and applications and designing and maintaining databases and infrastructures for top companies such as Tokopedia, Mercari, and Travelio. For the last five years, he has specialized in iOS software development, building high-quality applications and mentoring other junior engineers.

Portfolio

Mercari
Swift, Xcode, UIKit, iOS, Unit Testing, XCTest, Automated Testing...
Tokopedia
Swift, Jenkins, Xcode, Bazel, UIKit, iOS, Unit Testing, XCTest...
Travelio
JavaScript, Node.js, MongoDB, Express.js, Ubuntu, Swift, Android, NGINX, iOS...

Experience

Availability

Part-time

Preferred Environment

MacOS, Xcode, Visual Studio Code (VS Code)

The most amazing...

...thing I've developed is a feature that provided users with rewards, became the most valued product, and is still used today.

Work Experience

Software Development Engineer

2021 - PRESENT
Mercari
  • Enforced a critical feature within a small team to increase seller and buyer conversion rates and improve the company's potential revenue.
  • Supervised development and bug fixing of a critical module of the mobile application.
  • Implemented an overwrite of the legacy app using the latest technologies and architecture, such as SwiftUI, Bazel, composable architecture, and more.
  • Served as a member and guided new members to be integrated, understand the current technologies and architecture, and develop as fast as possible.
Technologies: Swift, Xcode, UIKit, iOS, Unit Testing, XCTest, Automated Testing, Model View ViewModel (MVVM), SwiftUI, GitHub, Reactive Programming, Figma, User Interface (UI), User Experience (UX), Mobile Development

Principal iOS Engineer

2017 - 2021
Tokopedia
  • Evolved to the technical lead of a team, established code style and guides, and mentored senior and junior team members.
  • Developed and maintained an in-house CI system using Jenkins and GitHub hook, handling hundreds of builds daily.
  • Improved time from over an hour to less than five minutes using Bazel, operating within a small team.
  • Created a gamification feature using animation and size calculation that became one of the main features of the company's iOS application.
Technologies: Swift, Jenkins, Xcode, Bazel, UIKit, iOS, Unit Testing, XCTest, Automated Testing, CI/CD Pipelines, Fastlane, Model View ViewModel (MVVM), GitHub, Reactive Programming, RxSwift, Objective-C, Core Animation, Figma, GraphQL, UI Animation, User Interface (UI), User Experience (UX), Mobile Development, Firebase

Lead Full-stack Software Developer

2014 - 2017
Travelio
  • Created and maintained RESTful API infrastructure from scratch using Node.js, Express.js, and MongoDB for supporting front-end clients and mobile apps.
  • Designed, implemented, and maintained database schema using MongoDB for quick data retrieval.
  • Maintained and improved servers to handle hundreds of requests per second using Ubuntu, NGINX, and load-balancing techniques.
  • Developed iOS and Android applications for users to be able to search for rentals, make reservations, and pay for them.
  • Worked closely with stakeholders to deliver the best product with minimal time and cost.
  • Led team members and set a high standard for code style.
  • Developed an iOS application that enables users to quickly contact customer service for any trouble regarding their reservation via real-time chat.
Technologies: JavaScript, Node.js, MongoDB, Express.js, Ubuntu, Swift, Android, NGINX, iOS, Objective-C, Amazon Web Services (AWS), Cloudflare, Load Balancers, Microservices, REST APIs, REST, RESTful Services, RESTful Microservices, Droplets, iOS API, iOS SDK, Swift 1, Swift 2, Database Management, Ajax, jQuery, jQuery UI, HTML, CSS, SSH

Lead Full-stack Developer

2012 - 2014
Code-O
  • Developed a point of sale and inventory application for hotels and travel services using C#.NET and WPF that became the number one top-selling application of the company and also one of the reasons the company got acquired.
  • Developed a social media application for iOS that enabled users to take pictures, use filters and editing, and allow their friends to guess what it is.
  • Worked closely with clients and team members, acting as project manager and developer to ensure good communication and perfect delivery of the product.
  • Developed a Point of Sale website using PHP, CodeIgniter, and MySQL for ordering gowns and accessories for university graduation ceremonies.
  • Created a project management system using PHP, JavaScript, HTML, and CSS for a medium-sized elevator company.
  • Developed a sales and inventory system using MongoDB, Play Framework, Java, and Backbone.js for small businesses to increase their efficiency and accuracy in managing their businesses.
Technologies: Android, iOS, Objective-C, iPad, Xcode, C#.NET, Visual Studio, Windows Presentation Foundation (WPF), JavaScript, HTML, CSS, PHP, CodeIgniter, REST, REST APIs, RESTful Development, NGINX, PhpMyAdmin, MySQL, Version Control, Code Versioning, Swift, Java, Play Framework, RockMongo, Apache, Backbone.js, Ajax, jQuery, jQuery UI

Gamification Feature | Tokopedia

A feature for the Tokopedia app shows an image of a colorful egg that, if tapped, is cracked open and gives the users a coupon or some prize. It involves complex animation and flexibility to receive any image from API that may or may not be an image of an egg.
2008 - 2012

Bachelor's Degree in Computer Science

Bina Nusantara University (BINUS) - Jakarta, Indonesia

Libraries/APIs

Node.js, RxSwift, Core Animation, REST APIs, Backbone.js, jQuery, jQuery UI, iOS API

Tools

Xcode, GitHub, Figma, Fastlane, Jenkins, NGINX, Bazel, Visual Studio, PhpMyAdmin, Apache

Frameworks

XCTest, Express.js, UIKit, SwiftUI, Windows Presentation Foundation (WPF), CodeIgniter, Play Framework, iOS SDK

Paradigms

Unit Testing, Mobile Development, Reactive Programming, Automated Testing, Model View ViewModel (MVVM), Visual Programming, REST, RESTful Development, Microservices

Languages

Swift, Objective-C, GraphQL, JavaScript, C#.NET, HTML, CSS, PHP, Java, Swift 1, Swift 2

Platforms

iOS, Firebase, Ubuntu, Android, Visual Studio Code (VS Code), Oracle Database, Amazon Web Services (AWS), Droplets

Storage

MongoDB, Database Management, MySQL, RockMongo

Other

Algorithms, Data Structures, CI/CD Pipelines, UI Animation, User Interface (UI), User Experience (UX), Computer Networking, iPad, Version Control, Code Versioning, Ajax, Cloudflare, Load Balancers, RESTful Services, RESTful Microservices, SSH

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