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Liu Zixing, JavaScript Developer in San Juan, Puerto Rico
Liu Zixing

JavaScript Developer in San Juan, Puerto Rico

Member since October 8, 2015
Liu is a software architect with comprehensive knowledge and experience in web and iOS application development. His mantra of quality over quantity always brings about impeccable online products. He is an early adopter of cutting-edge coding practices, frameworks, and the technologies. He communicates early and often while keeping up the great teamwork.
Liu is now available for hire



  • JavaScript, 9 years
  • Ruby on Rails (RoR), 6 years
  • Node.js, 6 years
  • React, 6 years
  • Ember.js, 5 years
  • Vue.js, 4 years
  • Angular, 4 years
  • Redux, 4 years
San Juan, Puerto Rico



Preferred Environment

Visual Studio, Sublime, Git

The most amazing...

...experience I’ve had as a software engineer was giving lectures on React.js and Flexbox to junior developers from the local development community.


  • Freelance Lead Front-end Developer

    2019 - 2019
    Belmont Technology (via Toptal)
    • Built graphs for geographical analysis using D3.js.
    • Refactored the existing React front-end for the elimination of code duplication.
    • Implemented custom zoom in/out effects with D3.js.
    • Figured out and introduced a new way of communication between different graph containers using Redux and component refs.
    • Suggested and helped to implement more effective Agile methodology techniques for the better management of the fast-paced project.
    Technologies: React, D3.js, Redux, HTML5, CSS3
  • Freelance Full-stack Developer

    2018 - 2018
    Linux Academy (via Toptal)
    • Helped the company quickly launch the new enterprise version in Angular 5.0.
    • Took part in the design and implementation process of the REST API in Ruby on Rails.
    • Handled complicated styling issues with Angular Material components.
    Technologies: Ruby on Rails, Angular 5
  • Freelance React Developer

    2018 - 2018
    MetTel Engineering (via Toptal)
    • Added independent features using React and Redux.
    • Utilized Storybook for the decoupled and fast-paced development of the UI/UX.
    • Familiarized myself with the already existing framework with minimal guidance and suggested more than five issues and suggestions in order to make it better.
    • Occasionally collaborated and wrote modules on the .NET-based back-end for effective routing.
    Technologies: React, .NET, Storybook
  • Freelance Front-end Developer

    2018 - 2018
    Acuity Scheduling (via Toptal)
    • Built a solid React-based code/architecture for the new SaaS branch of Acuity Scheduling.
    • Integrated a React application with the GraphQL database using Apollo.
    • Collaborated with the designer and back-end developer and suggested a few points that were accepted and implemented for an improved user experience.
    • Implemented highly complex render components and HOCs.
    • Documented the custom React components using Storybook.
    Technologies: React, Apollo, GraphQL, Ant, Test-driven Development
  • Freelance Node.js Expert (Conversion of a C# App)

    2017 - 2018
    DigiPro (via Toptal)
    • Supported the mobile application development with REST API using Node.js and Express.js.
    • Migrated a substantial MS SQL database to MySQL.
    Technologies: Node.js, Laravel
  • Software Engineering Consultant

    2016 - 2017
    One Solution
    • Created a Ruby on Rails engine for the company's proprietary help-desk archive.
    • Implemented continuous integration (CI) with CircleCI.
    • Wrote a developer guide for OpenCV API usage.
    • Aided in the implementation of Six Sigma principles onto the company's mainstream operations.
    • Promoted Agile methodology and contributed to the 23% increase in the annual performance of the team.
    • Turned a jQuery-based WYSWYG form editor to an Ember-based tool.
    • Supervised the development of two Angular 4 applications.
    Technologies: Ruby on Rails, Ember.js, Angular 4, Six Sigma, Agile Methodology, OpenCV
  • Lead Technical Developer

    2014 - 2015
    • Transformed jQuery-based front-ends to AngularJS.
    • Introduced Jira as the primary task management tool.
    • Established in-house coding principles based on Airbnb ESLint.
    • Implemented Devise in five Ruby-on-Rails authentication modules.
    • Implemented Passport.js in two Node.js/Express.js back-ends.
    Technologies: AngularJS, Node.js, Ruby on Rails, MongoDB
  • iOS Developer

    2012 - 2013
    Sky Knite, Inc.
    • Suggested and implemented Core Data for offline data access.
    • Integrated Socket.IO for a proprietary help-desk app.
    • Extended two iPhone apps' compatibility with iPad using Auto Layout.
    • Took part in the annual department performance review.
    • Communicated with overseas clients (in English).
    Technologies: Objective-C, Swift, Xcode, iOS SDK, Ionic, Angular
  • Front-end Developer

    2007 - 2012
    Yinxiangma Co., Ltd.
    • Contributed to three flagship products with AngularJS 1.4.
    • Led the in-house administrator panel development using Agile methodology.
    • Developed a REST API using Node.js and serialized it to integrate it with Ember's data store.
    • Assisted the QA team with the implementation of a Selenium web driver.
    • Mentored six team members on Git and SVN usage.
    Technologies: JavaScript, Angular.js, Ember.js, Node.js


  • Survey Builder and Dashboard (Node.js and Express.js) (Development)

    The backbone of this web application is Node.js and Express.js. The MVP was developed using Node.js and Express.js pair along with a famous authentication library called Passport.js.

    For the fast turnaround time, we kept to server-side rendering using Jade (now Pug) until the Beta version. After the Beta version was out, the front-end had to shift to the form of a single-page application. Thus, Ember.js was chosen to be the front-end framework that consumes the REST API provided by the back-end.

  • NFL Explorer with Angular 4, Firebase, and RxJS (Development)

    Taking on the Angular 2 codebase with a limited functionality, I managed to upgrade it to Angular 4 and introduced RxJS for a better asynchronous programming paradigm. Initially, the real-time feature of Firebase was not being utilized at all. I then introduced RxJS and the Observable/Subscription pattern which instantly made everything simpler by fully exploiting the real-time feature of Firebase.

  • MEAN-Based eCommerce Portal (Development)

    The MEAN stack was used to build this highly independent eCommerce portal. As it was way out of the traditional shopping sites, I had to put an emphasis on the dynamic features and ingenious building blocks.

    MEAN (MongoDB, Express.js, AngularJS, and Node.js) stack was used for this project. A Node.js and Express.js pair was used to build a robust back-end that provides REST API for the storefront.

    As the UX was directly related to the revenue generation, I planned and carried out an extensive set of unit and E2E tests. Karma, Jasmine, and Nightwatch were used for this purpose.

  • Device Monitoring Tool with AngularJS 1.6, Python, and Highcharts (Development)

    The device monitoring startup needed an all-in-one dashboard that could give an in-depth insight of the customers' registered devices. I took part in the design and implementation of the Django-based REST API and the documentation using Swagger.

    On the front-end, I built the dashboard in the form of SPA using AngularJS 1.6. Like the majority of the dashboards, it needed rich widgets, data tables, and visualizations. Highcharts was used to render highly intuitive data visualizations along with the ingenious two-way interactions; i.e. drawing a range on the chart and updating it on the fly.

  • iOS Image Processing Application (Development)

    OpenCV was used along with Core Image. The application had its value proposition in helping the site surveyors with a handy tool for detecting defects, marking them and archive the whole photo logs of such cases. I also developed a web-based admin portal that provides analytic data and searchable logs on company level.

  • Investment Data Visualization using React and D3.js (Development)

    My big data and data visualization skillset was put into practice on this project. In order to lay out a straight-forward component hierarchy and put more focus on the visualization and data processing, I chose to use React.js as the JavaScript framework to go with. Redux and Redux-Saga were used to encourage reactive and asynchronous programming.

    Using D3.js, the two-fold processed investment data was converted into a nice-looking and intuitive Force-directed graph.

  • A Ruby on Rails REST API for the Ember Front-End (Development)

    Aside from all the generic REST API principles, the Ember-compatible data format was customized for the highly autonomous Ember data model. For this, I used serializers and custom parameter processors in Ruby on Rails controllers. Here the property naming conventions mattered a lot. I also did test-driven development with RSpec and FactoryGirl.

  • Ember-based Drone Analysis Tool (Development)

    The project aimed to provide pilots and owners with the scientific insights to drone tracking, flight management, and on-the-map visualizations.

    The Ruby on Rails back-end supported the REST API and the front-end consumed the serialized data and presented it to the view using the object modeling mechanism of Ember.js. D3.js, Highcharts, and Mapbox were used for the data visualization and map integration.


  • Languages

    Haml, Pug, TypeScript, Sass, Less, JavaScript, CSS3, HTML5, Objective-C, CoffeeScript, ES7, PHP, Swift
  • Frameworks

    Redux, OAuth 2, Ember.js, Bootstrap 4, ZURB Foundation, Jasmine, iOS SDK, Express.js, Ruby on Rails (RoR), Vuetify.js, Core Data, Capybara, Angular, CodeIgniter, AngularJS
  • Libraries/APIs

    Vuex, Handlebars, Selenium WebDriver, Stripe API, D3.js, Highcharts, RxJS, Flexbox, Redux-saga, Node.js, jQuery, React, Vue.js 2, Vue.js, Nightwatch.js
  • Tools

    Auto Layout, RSpec, GitHub, Git, Sublime Text 3, Angular CLI, Karma, Mocha, Redux Thunk, Xcode
  • Paradigms

    Test-driven Development (TDD), Reactive Programming, Agile Software Development
  • Platforms

    Firebase, iOS, Android
  • Storage

    PostgreSQL, MongoDB, Elasticsearch, MySQL
  • Other

    Ember CLI


  • Bachelor's degree in Computer Engineering
    2001 - 2006
    Tsinghua University - Beijing, China
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