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Chris Liang
Verified Expert in Engineering
Software Developer
Vladivostok, Primorsky Krai, Russia
Toptal member since October 1, 2016
Bio
Chris loves creating web apps and iOS/Android apps. Over the past decade, he's developed more than 100 apps—providing a comprehensive UI/UX in geolocation service, real-time messaging, and other social features. He specializes in developing desktop and mobile apps related to real estate and food industries. Chris is an open-minded and personable developer who loves working with other developers in a team environment.
Portfolio
LJA Engineering, Inc
Angular, MongoDB, GraphQL, Express.js, Node.js, NgRx...
Everfit, Inc. (via Toptal)
React Native, GraphQL, Apollo, React, JavaScript, TypeScript, React Redux, Vue...
Enroute 911
Google Maps, Mapbox, Redux-Saga, React Native, iPad, JavaScript, React Redux...
Experience
- HTML - 10 years
- Ruby on Rails (RoR) - 7 years
- Swift - 5 years
- React - 5 years
- Node.js - 5 years
- React Native - 4 years
- React Redux - 4 years
- Vue - 4 years
Preferred Environment
Visual Studio Code (VS Code), Android Studio, Xcode
The most amazing...
...thing I've built was a fitness coach management system in React (Apollo GraphQL) along with a React Native mobile app.
Work Experience
Mid/Senior Angular, Express, and GraphQL Developer
2019 - 2024
LJA Engineering, Inc
- Refactored an Angular 7 codebase to improve application performance, reducing page load time by 25% through efficient state management using NgRx and optimizing rendering logic for client-facing features.
- Led the resolution of 100+ high-priority bugs within the CRM application, improving user experience and application stability. Delivered fixes in an average turnaround time of 2-3 days per issue.
- Developed and deployed new client-facing features that integrated with MongoDB and GraphQL APIs, increasing user engagement by 15% by enhancing client event tracking and project management workflows.
- Collaborated with the product manager to prioritize and execute over a hundred backlog tasks in Jira, ensuring timely delivery of key enhancements and bug fixes while maintaining a focus on reducing technical debt.
- Optimized GraphQL queries to reduce API response time by 40%, improving the overall performance of client data retrieval in the application.
- Implemented multiple API integrations between the CRM platform and third-party marketing tools, enabling seamless event management and lead tracking, which contributed to a 20% increase in marketing campaign efficiency.
- Conducted code reviews and mentored junior developers, ensuring adherence to best practices in Angular, NgRx, and API design, which improved overall team productivity and code quality by 30%.
- Reduced database query complexity in MongoDB by restructuring indexes and optimizing data models, resulting in a 35% improvement in query performance for high-volume client data operations.
- Led the migration of legacy features to modern Angular practices and NgRx state management, ensuring the long-term scalability of the CRM platform while reducing technical debt by 50%.
- Enhanced client reporting functionality by developing custom GraphQL resolvers and aggregation queries, allowing project managers to generate real-time, actionable insights that improved client relationship management.
Technologies: Angular, MongoDB, GraphQL, Express.js, Node.js, NgRx, Agile Software Development, React, Redux-Saga, Redux Thunk, TypeScript, React Apollo, React Redux, Redux, NgRx/store, JavaScript, Vue, HTML
Senior Full-stack Developer
2019 - 2019
Everfit, Inc. (via Toptal)
- Developed a dashboard for managing coaches with full CRUD functionality using React and Apollo GraphQL. Built cross-platform iOS and Android apps in React Native, delivering efficient data management and seamless user experiences.
- Architected customized webhooks for Twilio to facilitate seamless messaging between clients and coaches, ensuring efficient and reliable communication through real-time notifications and message delivery.
- Implemented automated cron jobs to process incoming client SMS messages and trigger timely notifications to coaches, ensuring smooth and responsive communication workflows.
- Designed and implemented a comprehensive survey system for web and mobile applications, delivering a seamless user experience across platforms.
- Developed and maintained database migrations and seed scripts using Knex.js to ensure efficient and reliable data structure management, enabling seamless application deployment and consistent data population across environments.
- Leveraged the Serverless Framework to build and deploy scalable, event-driven applications, optimizing resource usage and streamlining the development of cloud-native solutions.
Technologies: React Native, GraphQL, Apollo, React, JavaScript, TypeScript, React Redux, Vue, Angular, HTML
Senior Front-end Developer
2018 - 2019
Enroute 911
- Enhanced code quality by upgrading legacy JavaScript to ES7 and implementing modularization, improving maintainability, readability, and scalability.
- Achieved a 300% reduction in initial loading time by identifying and resolving logical errors in the code, significantly improving application performance and user experience.
- Integrated Google Maps, Mapbox, and various other map SDKs to deliver dynamic and interactive mapping features, enhancing the application's functionality and user experience.
- Implemented Redux-Saga to manage background API calls efficiently, improving application performance and ensuring seamless data synchronization.
Technologies: Google Maps, Mapbox, Redux-Saga, React Native, iPad, JavaScript, React Redux, Angular, HTML
Senior Mobile Developer
2018 - 2018
NZXT
- Developed a mobile app to get and update the PC status while playing games.
- Utilized BLE technology to get and connect with devices near a mobile phone.
- Called RESTful APIs for devices far away and used socket connection for devices near mobile phone to get the realtime data of the PC.
- Used GCD multithreading to call several APIs at once.
- Implemented Redux-saga to keep calling RESTful APIs in the background.
Technologies: Android, Swift, React Native, TypeScript, React Redux, Angular, HTML
Senior Full-stack Developer
2017 - 2018
Flexible Fitness, LLC
- Updated non-structured code to MVC architecture.
- Integrated Apple HealthKit and Google Fit for retrieving user health information such as the number of steps and weight.
- Integrated Apple Pay and Google Pay for in-app purchase function.
- Integrated OneSignal for push notification.
- Developed the front end in React.js(Redux Saga) and the back end in Node.js (ExpressJS).
- Implemented Sketch design to pure HTML/CSS.
- Used Bluetooth Beacon to connect with fitness devices.
Technologies: Redux-Saga, Express.js, Node.js, React Native, TypeScript, React Redux, HTML
iOS Developer
2016 - 2016
MeeCard
- Implemented BaaS using Parse.
- Developed an offline mode using local storage.
- Helped to develop the business requirements.
- Developed a push notification using APNs.
Technologies: Git, Objective-C
iOS Developer
2016 - 2016
Textgreets
- Developed real-time messaging using QuickBlox.
- Implemented geofencing using Google Maps SDK and Core Location.
- Integrated an in-app payment using Stripe, ApplePay, and PayPal.
- Created UI animations using Core Animation.
- Developed an offline mode using CoreData and Realm.
- Made push notification using OneSignal.
- Developed unit testing and UI testing.
Technologies: JavaScript, Objective-C, Git, Swift
Senior iOS Developer
2014 - 2016
TextUs Biz
- Provided the business logic needed for point of sales.
- Developed an offline mode using Core Data.
- Created a payment integration using Braintree.
- Enabled a credit card validation feature using Card.io.
- Implemented Apple Pay.
- Used WatchKit and OpenGL.
Technologies: Git, Swift, .NET, Objective-C
iOS Developer
2013 - 2016
RapidSOS
- Built a location-based service using Core Location and Google Maps SDK.
- Created a push notification-based messaging service.
- Developed VoIP call using PJSIP library.
- Created UI and unit testing using XCTest.
- Developed an offline mode using Core Data.
Technologies: Git, JavaScript, Swift, Objective-C, iOS
iOS Developer
2015 - 2015
AppleSolutions DK
- Implemented a Shopify Client SDK and a Google Maps SDK.
- Added Apple WatchKit.
- Created a beacon using Estimote SDK.
- Added a payment integration using Apple Pay.
- Implemented a 3D touch feature.
Technologies: Git, Objective-C
iOS Developer
2014 - 2014
Beero
- Created rich animations using UIkit and Core Animation.
- Developed an offline mode.
- Enabled geofencing using Core Location and Google Maps SDK.
- Implemented a payment integration using PayPal.
Technologies: Git, iOS, Objective-C
Experience
TXG Mock Data Manager
A manager class designed to manage mock data. This class was necessary because the back-end infrastructure was not yet available, and it was required to make the application functional for a presentation.
To simulate the back-end functionality, the manager class loads PLIST files from an app bundle and utilizes them. It should be noted that this manager class is intended to be replaced by actual managers that communicate with the back end once it becomes available.
To simulate the back-end functionality, the manager class loads PLIST files from an app bundle and utilizes them. It should be noted that this manager class is intended to be replaced by actual managers that communicate with the back end once it becomes available.
Beero iOS App
• Created rich animations using UIkit and Core Animation. • Developed an offline mode.
• Enabled geofencing using Core Location and Google Maps SDK.
• Implemented a payment integration using PayPal.
• Enabled geofencing using Core Location and Google Maps SDK.
• Implemented a payment integration using PayPal.
AppleSolutions
• Implemented a Shopify Client SDK and a Google Maps SDK.
• Added Apple WatchKit.
• Created a beacon using Estimote SDK.
• Added a payment integration using Apple Pay.
• Implemented a 3D touch feature.
• Added Apple WatchKit.
• Created a beacon using Estimote SDK.
• Added a payment integration using Apple Pay.
• Implemented a 3D touch feature.
RapidSOS iOS and Android
• Built a location-based service using Core Location and Google Maps SDK.
• Created a push notification-based messaging service.
• Developed VoIP call using PJSIP library.
• Created UI and unit testing using XCTest.
• Developed an offline mode using Core Data.
• Created a push notification-based messaging service.
• Developed VoIP call using PJSIP library.
• Created UI and unit testing using XCTest.
• Developed an offline mode using Core Data.
TextUs Biz
• Provided the business logic needed for point of sales.
• Developed an offline mode using Core Data.
• Created a payment integration using Braintree.
• Enabled a credit card validation feature using Card.io.
• Implemented Apple Pay.
• Used WatchKit and OpenGL.
• Developed an offline mode using Core Data.
• Created a payment integration using Braintree.
• Enabled a credit card validation feature using Card.io.
• Implemented Apple Pay.
• Used WatchKit and OpenGL.
Textgreets
• Developed real-time messaging using QuickBlox.
• Implemented geofencing using Google Maps SDK and Core Location.
• Integrated an in-app payment using Stripe, ApplePay, and PayPal.
• Created UI animations using Core Animation.
• Developed an offline mode using CoreData and Realm.
• Implemented push notification using OneSignal.
• Developed unit testing and UI testing.
• Implemented geofencing using Google Maps SDK and Core Location.
• Integrated an in-app payment using Stripe, ApplePay, and PayPal.
• Created UI animations using Core Animation.
• Developed an offline mode using CoreData and Realm.
• Implemented push notification using OneSignal.
• Developed unit testing and UI testing.
MeeCard
• Used Parse for the back end.
• Developed an offline mode using local storage.
• Helped to develop the business requirements.
• Developed push notifications using APNs.
• Developed an offline mode using local storage.
• Helped to develop the business requirements.
• Developed push notifications using APNs.
Flexible Fitness React Native App
• Updated the non-structured code base to MVC architecture
• Integrated HealthKit and GoogleFit for getting user details such as number of steps, weight, blood pressure, etc.
• Integrated Apple Pay and Google Pay for in app purchase feature
• Pixel perfect implementation of the new UI given by the client
• Used React.js(Redux-saga) for front end, Pure Javacript(ES5), and Node.js(ExpressJS) for backend
• Implemented Sketch design to pure HTML/CSS
• Integrated HealthKit and GoogleFit for getting user details such as number of steps, weight, blood pressure, etc.
• Integrated Apple Pay and Google Pay for in app purchase feature
• Pixel perfect implementation of the new UI given by the client
• Used React.js(Redux-saga) for front end, Pure Javacript(ES5), and Node.js(ExpressJS) for backend
• Implemented Sketch design to pure HTML/CSS
KudosFit (via Toptal)
https://www.kudos.fit/The purpose of this project was to provide real-time coaching to clients via a mobile app helmed by actual coaches.
Role: Senior Full-stack Developer
I built both desktop web app and mobile app in React (Apollo GraphQL) and React Native.
This project used Apollo GraphQL with a serverless framework for the desktop app. It was already on air and I needed to write a lot of migration scripts and seeding every time, I wrote a new function or add a new feature based on Knex.
I also built a dashboard to manage the coaches' apps (CRUD operation) and clients' iOS & Android mobile apps. I also wrote customized webhooks for Twilio messaging between clients and coaches and cron jobs to send notifications to coaches based on the SMSs received from the clients.
I was able to fix several bugs and add more than five new features of the app in less than two months.
Role: Senior Full-stack Developer
I built both desktop web app and mobile app in React (Apollo GraphQL) and React Native.
This project used Apollo GraphQL with a serverless framework for the desktop app. It was already on air and I needed to write a lot of migration scripts and seeding every time, I wrote a new function or add a new feature based on Knex.
I also built a dashboard to manage the coaches' apps (CRUD operation) and clients' iOS & Android mobile apps. I also wrote customized webhooks for Twilio messaging between clients and coaches and cron jobs to send notifications to coaches based on the SMSs received from the clients.
I was able to fix several bugs and add more than five new features of the app in less than two months.
CRM Application
The CRM application tracks client contacts and relationships with project managers and helps plan client events and similar tasks around managing marketing activities for clients. The application has been in production for six years.
Updates included adding multiple new features, bug fixes, and reducing some technical debt. There was a detailed, prioritized backlog in Jira outlining all tasks.
In this role, I maintained and enhanced an internal CRM application built with Angular 7, NgRx, Node.js/Express, GraphQL, and MongoDB. I focused on bug fixes, performance optimizations, and new feature development, improving the user experience and application stability. My notable accomplishments include reducing load times by 25%, optimizing API performance by 40%, and resolving 50+ critical issues. I worked closely with a product manager to prioritize tasks, mentored junior developers, and streamlined integrations with third-party tools to improve client event management. My work helped improve both platform performance and overall team efficiency.
Updates included adding multiple new features, bug fixes, and reducing some technical debt. There was a detailed, prioritized backlog in Jira outlining all tasks.
In this role, I maintained and enhanced an internal CRM application built with Angular 7, NgRx, Node.js/Express, GraphQL, and MongoDB. I focused on bug fixes, performance optimizations, and new feature development, improving the user experience and application stability. My notable accomplishments include reducing load times by 25%, optimizing API performance by 40%, and resolving 50+ critical issues. I worked closely with a product manager to prioritize tasks, mentored junior developers, and streamlined integrations with third-party tools to improve client event management. My work helped improve both platform performance and overall team efficiency.
Education
2007 - 2009
Master's Degree in Computer Engineering
Far Eastern Federal University - Vladivostok, Russia
2003 - 2007
Bachelor's Degree in Computer Engineering
Far Eastern Federal University - Vladivostok, Russia
Skills
Libraries/APIs
CocoaPods, Node.js, React, Facebook Login, Parse SDK, Plaid API, Instagram API, Google Places API, Google Maps SDK, Google Geocoding API, Yelp API, Foursquare API, Mapbox iOS SDK, Braintree API, React Redux, Vue, Twilio API, Redux-Saga, Google Maps, NgRx, NgRx/store
Tools
Xcode, Android Studio, Jira, Trello, Asana, Basecamp, OneSignal, React Apollo, Knex.js, MongoLab, Git, Redux Thunk
Languages
PHP, JavaScript, Swift, Objective-C, GraphQL, HTML, CSS, SCSS, TypeScript, C++, C, Java
Frameworks
Core Bluetooth, Cocoa, React Native, Angular, Express.js, Bootstrap, RealmSwift, MapKit, Serverless Framework, Laravel, Ruby on Rails (RoR), .NET, Redux
Paradigms
Model View ViewModel (MVVM), MVC Design, Agile Software Development, Agile, Model View Controller (MVC), Continuous Deployment, Continuous Integration (CI), Scrum
Platforms
MacOS, iOS, Amazon EC2, Firebase, Visual Studio Code (VS Code), iOS 12, Twilio, Oracle, Linux, WordPress, Android, Bluetooth Low Energy (LE), Mapbox
Storage
MSSQLCE, MySQL, Amazon S3 (AWS S3), Elasticsearch, MongoDB, Realm, MySQLdb, SQLite
Other
Web Development, iPhone, iPad, Google Login, Stripe Payments, Geolocation, Data Mining, Apollo, iBeacon, Serverless, Bluetooth Beacons, Development, Responsive UI
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