Marcus Hsu
Verified Expert in Engineering
Full-stack Developer
Bellevue, WA, United States
Toptal member since May 19, 2020
Marcus has over a decade of experience in front-end development, building React websites and developing iOS and Android apps in React Native for the past several years. He has helped at least 31 enterprises and startup clients to design and build high-quality cross-platform apps using React, React Native, and Node.js. Marcus has also built enterprise-scale apps that have impacted over 30 million users in 140 countries.
Portfolio
Experience
Availability
Preferred Environment
Node.js, Redux, Sass, JavaScript, React, React Native, TypeScript, Jest, Cross-platform, Web & Mobile Applications
The most amazing...
...projects I've built from scratch using React and React Native are enterprise-scale web and mobile apps that impact over 30 million users in 140 countries.
Work Experience
Hands-on Tech Lead
A Residential Brokerage Company
- Led a team of front- and back-end developers to spearhead the technical direction for the luxury bidding platform's minimum viable product.
- Cooperated constantly with the PM and UX designer to make high-level architectural decisions and led design meetings, making most of the final technical decisions.
- Performed hands-on coding daily to accomplish the client's urgent requests and critical bug fixes and guided each junior developer to ensure the team met every sprint deadline.
- Mentored junior developers regarding their code and approach to solving problems.
- Reviewed every pull request in great detail before merging into the codebase to ensure the highest code quality at all times.
- Engaged in solely maintaining the codebase after product launch as I deeply understood how each piece of code functions for 90% of the entire codebase.
- Accomplished several critical bug fixes, UX improvements, and new large features.
Tech Lead
A Real Estate Platform Provider
- Led a newly-found design system team to spearhead its technical direction and provided consultation for several application teams.
- Assessed the current codebase and devised strategies to incorporate the new design system into the existing apps.
- Developed a centralized reusable component library from scratch, providing a set of standards to guide its usage. It increased the productivity of application teams to focus on business logic without building their own components.
- Drove the adoption of the centralized reusable component library to be consumed by several React and React Native applications. It involved countless conflict resolution, migration, testing, and bug fixes before releasing each app back to production.
- Pioneered a way to build and run the React Native components' Storybook on iOS and Android devices and any web browser, as there was no existing solution. It enabled the components to be built once and used everywhere.
- Set up a comprehensive unit test framework to test most kinds of user interactions on mobile devices and stimulated a native mobile environment where the framework would run. It was built with Jest, a testing library, and several others.
- Created a design tokens build system from scratch to allow developers to style once and consume it on any platform. It became a single place to create or edit reusable style guides and assets, making the styles consistent across different apps.
- Built a library to handle the responsiveness of mobile devices since there is no out-of-the-box solution in React Native to set the breakpoints like media queries on the web.
Senior React Native and React Engineer
A State University Technology Office
- Built an Android app to manage self-sovereign identity using blockchain technology. It uses complex native modules to connect to each user's wallet on the blockchain and was built with React Native, TypeScript, D3.js, Hyperledger Aries, and Indy SDK.
- Developed an admin console—solely from scratch to product launch—to manage identities and credentials on the blockchain. It has complex charts, graphs, and animation for data visualization and is built with React, TypeScript, and Material UI.
- Architected and implemented the admin console application's internationalization and localization features to make it available to all the supported countries.
Top Full-stack Developer
A Healthcare Staffing Technology Platform
- Engaged as the main contributor to Android mobile apps, impacting 350,000+ nurses by enabling them to log their times easily. It involved complicated photo taking, scanning, and identity verification and was built with React Native and TypeScript.
- Completed several painful migrations of native modules to make an existing sophisticated Android app cross-platform so it could work and be developed on iOS and Android in a single codebase.
- Drove the front- and back-end development of real-time geolocation tracking. It involved background location-tracking and geofencing with battery-conscious motion-detection intelligence for iOS and Android using React Native and the Google Maps API.
- Set up the complicated build, deployment, beta testing, release, and code signing processes on the App Store and Google Play Store for several different environment settings.
Senior React Native and React Developer
A Healthcare Digital Platform Provider
- Used React Native, React Native for Web, and TypeScript to build an iPad application to connect patients, doctors, and health plans seamlessly. It later extended its capability to have cross-platform support, such as web and Android tablets.
- Developed solely and from scratch to product launch a healthcare app related to PIP diabetes, which impacted 800,000+ users. It was built with React and TypeScript.
- Implemented a proof of concept to experiment with different trending technologies and fancy user experiences, such as a flowchart, to spearhead the next generation of healthcare software.
- Built several other healthcare cross-platform applications to enable data-driven insights for patients, doctors, and administrators, leveraging artificial intelligence and machine learning technology.
Senior Front-end Software Engineer
ADP Innovation Lab
- Led the front-end development of the new user onboarding and account setup workflows for both web and mobile, which impacted 30+ million users. It is built with React and React Native.
- Spearheaded the front-end development of the internationalization support for all client-critical pages to make the ADP website available in 140+ countries.
- Served as the tech lead of a team of more than ten engineers in building a new identity control center platform for both web and mobile, which impacted over 20,000 users. It was built with React, React Native, Node.js, MySQL, and Couchbase.
- Led the development of a new multi-factor authentication framework along with spearheading the framework adoption initiative across multiple product teams to make it available in all ADP's core products for 15,000+ companies' payrolls worldwide.
- Onboarded, trained, and mentored 10+ junior-, mid-, and senior-level developers who joined my team and had them follow JavaScript, React, Redux, and Sass best coding practices.
- Contributed to product and roadmap planning and UX design sessions with product managers, clients, and UX designers.
- Achieved a proven track record that has allowed me to step up and manage the team from time to time to meet critical product deadlines, even when faced with minimal developer resources.
- Took full responsibility and ownership of the codebase of client-critical identity-related front-end workflows; became the main point of contact and stayed on call for any production issues, feature requests, and support.
- Demonstrated and frequently presented the status of the development I have been leading and the results of my research at leadership conferences.
Full-stack Software Engineer
ADP
- Architected and designed a proprietary authentication and authorization framework for web and mobile applications. The framework contains three granted patents with my name on all of them.
- Worked with 20 developers to complete the development of the proprietary authorization framework using React, Node.js, MongoDB, MySQL, Scala, and Casandra.
- Designed and developed a Selenium end-to-end regression test framework to replace manual tests companywide. Ensured the framework covered not only all the common use cases and edge cases but all major browsers, as well as IE and IE Edge.
- Ensured 100% unit testing code coverage for all major front- and back-end repositories using Jest, Mocha, and Chai.
- Rolled out a database migration to switch from MongoDB to Couchbase Server for all the microservices in the team.
- Adhered to the highest security standards for front- and back-end development, contributing to ADP's ranking as 1st on the Security 500.
- Executed in a highly experimental and R&D-oriented domain to stay on the cutting edge of trending open-source technologies.
- Guaranteed each release's quality and continuous deployment by automating the building process and comprehensive regression testing in Jenkins.
- Worked closely with the infrastructure team to constantly update and patch all applications and microservices so that the team could stay up to date with new technology stacks and security requirements and achieve stronger performance.
- Secured integration tests covered all the possible interactions between services and databases in a real-cloud environment.
Full-stack Web Developer
Acupay
- Developed solely and from scratch to launch a global asset management services web app with a monthly value of $500,000. It was built with AngularJS, Node.js, Express.js and Jade, Microsoft SQL Server, Grunt, and multi-factor authentication (MFA).
- Built by myself and from scratch to launch a European tax-processing-services web app with a monthly value of $100,000. It was built with Angular, Node.js, Hapi.js, Handlebar.js, and Microsoft SQL Server.
- Implemented a centralized mailing server to manage all internal email in a secure channel and provide an admin dashboard with real-time mailing status updates and stats charts. It was built with React, Flux, WebSockets, D3.js, and Grunt.
Teaching Assistant
Columbia University
- Assisted the professor in supervising over 50 students concerning their big data programming projects using Hadoop 2, Pig, Mahout, GraphDB, Hive, HBase, and Oozie.
- Offered support to guide and debug all course-related resources, assignments, and projects for over 100 students every week.
- Hosted teaching assistant sessions for live demos to demonstrate how to build, run, and develop Pig, Hive, HBase, Oozie, Mahout, and GraphDB in a Hadoop 2 ecosystem and how to apply them to a real-world problem.
Experience
Arthur Murray Official (iOS and Android)
https://www.arthurmurrayofficial.com/It is built for the biggest ballroom dance studio franchise in the world. It uses React Native for the front end and Node.js and MySQL for back-end big data processing.
I am not working directly for Arthur Murray but for FHConcept, which works directly with Arthur Murray.
Pinto (iOS and Android)
It's built with React Native and GraphQL for the front end along with an integration with the existing back end.
It's available for download in the App Store (Apple.co/2Qz6VEj) and Play Store (Bit.ly/3ap7OGK).
Pacesetter (iOS)
It's built with React Native for the front end as well as geolocation, motion tracking, and iTunes integration; Firebase for back-end data storage. It's currently in beta testing and will be available in the App Store very soon.
Get Apollo (iOS and Android)
https://www.getapollo.in/It's built with React Native for the front end; Firebase for back-end storage, OAuth authentication, and app analytics.
It's available for download in the App Store (Apple.co/2Lh7oq3) and Play Store (Bit.ly/2WhuujG).
Circlus Connect (iOS)
It's built with React Native for the front end and Node.js, MongoDB, and Stripe API for back-end payment processing. It's available for download in the App Store (Aapple.co/2VGkTC3).
Local Detour (iOS)
It's built with React Native for the front end; Firebase for back-end data storage and OAuth authentication. It's available for download in the App Store (Apple.co/2VEdHX6).
Future Plans (iOS)
It's built with React Native and Expo for front-end rapid prototyping. It's currently in beta testing and will be available in the App Store very soon.
Wonda Shop (iOS and Android)
It's built with React Native and Expo for front-end rapid prototyping. It's currently in beta testing and will be available in the App Store and Play Store very soon.
Goti (iOS and Android)
It's built with React Native and Expo for front-end rapid prototyping. It's currently in beta testing and will be available in the App Store and Play Store very soon.
Lifion by ADP (Web)
It's built with React, Redux, and several proprietary custom-built components.
Play Nice (Web)
https://staging.playniceapp.com/homeIt's built with React for the front end and Node.js, MongoDB, Stripe API, Twillio API, Gmail API for the back end. Feel free to reach out for more details.
Taiwan Society for Risk Analysis (Web)
It's built with React for the front end and Node.js, MongoDB, Firebase for back-end data storage. Feel free to reach out for more details about the project.
Sugarpost (Web)
It's built with Angular for the front end and Node.js and MongoDB for back-end big data processing. Feel free to reach out for more details about the project.
CMTech (Web)
It's built with Angular for the front end and Node.js and MongoDB for back-end big data processing. Feel free to reach out for more details about this project.
Source Code for a React Native App
https://github.com/kiddkevin00/get-apolloSource Code for a React App (Full-stack)
https://github.com/kiddkevin00/top-timesEducation
Master's Degree in Electrical Engineering, Specializing in Computer Science
Columbia University - New York, United States
Bachelor of Science Degree in Engineering Science, Specializing in Computer Science
National Taiwan University - Taipei, Taiwan
Skills
Libraries/APIs
React.js, Node.js, React.js, REST API, Redux-Saga, React.js, React Redux Form, Formik, React.js, D3.js, Stripe Development, Stripe Connect API, Jenkins Pipeline
Tools
WebdriverIO, Webpack, Expo, React Native, Jira, ExpoKit, Mocha, NPM, Sequelize, Figma, Zeplin Design, Amazon Cognito, Grunt, InVision
Languages
SCSS, ES7, JavaScript, HTML5, CSS, HTML, Sass, ECMAScript (ES6), ES8, TypeScript, CSS3, TypeScript 3, GraphQL, SQL
Frameworks
React Native, Jest, Redux, Flux, JSON Web Tokens (JWT), Material UI, OAuth, Bootstrap, Selenium, Hadoop
Paradigms
Agile Development, Mobile App Design, Unit Testing, Agile Development, Scrum Master Consulting, App Development, Web Architecture, Responsive Web Design, Functional Programming, Cross-Platform
Platforms
Firebase, Docker, Mobile App Design, Linux, iOS, Android, AWS
Storage
MongoDB, MySQL, SQL Server, PostgreSQL, NoSQL, Amazon S3
Industry Expertise
Banking Consulting
Other
RESTful Microservices, Mobile App Design, Web App Deployment, Mobile App Design, APIs, Front-end, UX Development, UI Development, Full-stack, NativeBase, Single-page Applications (SPAs), SaaS, Architecture, Web Development, API Applications, Web Development, Cloud Engineering, Mobile Apps, Web Application, UI Development, Computer Science, Engineering, Software Architecture, Responsive Web Development, Minimum Viable Product (MVP), Containers, Design Consulting, Technical Consulting, Web Consulting, Interim CTOs, Mobile UI Design, Software Development, Styled-components, Web & Mobile Applications, Cross-platform Testing, Cross-platform App Development, Performance, Monorepos, Mobile App Design, Stripe Payments, Leadership, Geolocation, Airtable, Technical Leadership, System Security, React Native Bridge, AWS, WebSockets, Database, Electrical Engineering
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