Marshall Shen, Full-stack Developer in Chicago, United States
Marshall Shen

Full-stack Developer in Chicago, United States

Member since September 13, 2022
Marshall is a technical leader with 10+ years of experience. He has worked with various tech companies, ranging from seed startups to Fortune 100 companies in the fintech and healthcare industries. Marshall delivers innovative solutions using Ruby, Terraform, Java, Python, and other technologies.
Marshall is now available for hire

Portfolio

  • Venmo
    Python 3, Docker, Java, Ruby, Django, Technical Leadership, React...
  • Braintree
    Ruby, Ruby on Rails API, Java, Terraform, PostgreSQL, API Architecture...
  • PatientPoint
    Ruby, Vue, Ruby on Rails API, Technical Leadership, PostgreSQL, AWS...

Experience

Location

Chicago, United States

Availability

Part-time

Preferred Environment

MacOS

The most amazing...

...app I've built is Venmo, extending it with consumer financial products such as credit and debit card.

Employment

  • Senior Staff Software Engineer

    2019 - PRESENT
    Venmo
    • Developed a credit card product that scaled to more than 500,000 active users, with over $1 billion annual transaction processing volume.
    • Migrated a monolithic Python Django application into a microservices architecture, with a React web front-end, MySQL and DynamoDB as data storage, and Kafka as data streaming.
    • Functioned with technical leadership, overseeing and mentoring over 40 software engineers within the organization.
    Technologies: Python 3, Docker, Java, Ruby, Django, Technical Leadership, React, API Architecture, Fintech, MySQL, AWS, Bash, TypeScript, AWS RDS, Software Development, Algorithms, MongoDB, HTML, JavaScript, Python, Ruby on Rails (RoR), Kubernetes, Test-driven Development (TDD), APIs, Google Cloud, Firebase, Cloud Firestore, Back-end, Amazon Web Services (AWS), Back-end Development, Git, Amazon EKS, Web Development, RESTful APIs, Spring, Spring Boot, Unit Testing, Integration Testing, Software Testing Automation Framework (STAF), MUI (Material UI), UI, MUI CSS, CSS, Node.js, GraphQL, OpenAPI, Full-stack, Linux, ESLint, Enterprise, Enterprise Systems, Software Architecture, Team Leadership, Jira, Project Management, Slack, GitFlow, Agile Project Management, Architecture
  • Staff Software Engineer

    2018 - 2019
    Braintree
    • Built a payment processing solution for enterprise merchants like Uber and Airbnb and handled a daily processing volume of over $10 billion using Ruby on Rails, Postgres DB, and Kafka stream.
    • Created banking integration with National Australian Bank to launch payment processing service across all Braintree merchants in Australia.
    • Oversaw a financial audit process to ensure the financial ledger met compliance requirements.
    Technologies: Ruby, Ruby on Rails API, Java, Terraform, PostgreSQL, API Architecture, Technical Leadership, Software Development, QuickBooks API, Algorithms, HTML, Angular, JavaScript, Python, Ruby on Rails (RoR), Kubernetes, RabbitMQ, Test-driven Development (TDD), APIs, Back-end, Amazon Web Services (AWS), Back-end Development, Git, Web Development, RESTful APIs, Spring, Spring Boot, Unit Testing, Integration Testing, Software Testing Automation Framework (STAF), UI, CSS, Bootstrap, Node.js, OpenAPI, Full-stack, Linux, Enterprise, Enterprise Systems, Software Architecture, Team Leadership, Jira, Project Management, Slack, GitFlow, Agile Project Management, Architecture
  • Senior Software Engineer

    2015 - 2017
    PatientPoint
    • Launched a new product that managed digital content across 10,000+ IoT devices. Used Ruby on Rails for the back end, Vue.js for the front end, and Postgres DB as data storage.
    • Acted as a tech lead for a team of ten developers and prioritized development tasks with the product and leadership team.
    • Designed RESTful APIs and relational database systems for healthcare content streaming from scratch.
    Technologies: Ruby, Vue, Ruby on Rails API, Technical Leadership, PostgreSQL, AWS, Software Development, Algorithms, HTML, JavaScript, Chrome Extensions, Ruby on Rails (RoR), Test-driven Development (TDD), APIs, Back-end, Amazon Web Services (AWS), Back-end Development, Git, Heroku, Web Development, RESTful APIs, Unit Testing, Integration Testing, Software Testing Automation Framework (STAF), UI, CSS, OpenAPI, Full-stack, Linux, Enterprise, Enterprise Systems, Software Architecture, Jira, Project Management, Slack, GitFlow, Agile Project Management
  • Software Engineer

    2012 - 2015
    Groupon
    • Launched an internal accounting service to help merchant payments and developed payment algorithms that processed more than 1 billion USD of payments.
    • Developed and maintained the Ruby on Rails app with more than 100,000 merchants globally.
    • Worked with the Groupon finance and accounting team to help process and reconcile payments.
    Technologies: API Architecture, AWS, Computer Security, Software Development, QuickBooks API, Algorithms, HTML, JavaScript, Ruby on Rails (RoR), Test-driven Development (TDD), APIs, Back-end, Back-end Development, Git, Heroku, Web Development, Java, RESTful APIs, Spring, Spring Boot, Unit Testing, Integration Testing, Software Testing Automation Framework (STAF), UI, CSS, OpenAPI, Full-stack, Linux, Enterprise, Enterprise Systems, Software Architecture, Jira, Project Management, GitFlow, Agile Project Management

Experience

  • Venmo Credit Card
    https://venmo.com/about/creditcard/

    The Venmo Credit Card allows users to earn custom cash back to send, spend, or auto-purchase the crypto of their choice from their Venmo account.

    I was a tech lead for this project, leading the high-level architectural design and guiding 40+ software engineers.

  • HackerPen
    https://hackerpen.io

    HackerPen is an interactive, online peer-to-peer mock interview platform that allows people to practice technical interviews with each other using video or audio chat and collaborative coding and drawing pads, all in one web app.

    I created this platform and launched it in April 2022. As of September 2022, the platform is running with 300+ active users.

  • Maestro

    A mobile app that helps people practice sight-reading music.

    The technology used: React Native, AWS Lambda, with RESTful APIs.

    The app achieved over 2,000 downloads during the first six months of launch on iOS and the Google app store.

  • BuildU

    A student engagement application focused on American universities and colleges. The system was built on Ruby on Rails, React and React Native.

    I worked as the CTO of the company, and I was in charge of building the application and managing the software development process.

  • Kana - Learn Japanese

    A mobile app that teaches people Japanese. The app was released on the iOS app store in 2019, and it teaches people Hiragana through flashcards and pop quizzes. The app had more than 1,000 downloads, although it's no longer under maintenance.

Skills

  • Languages

    Python 3, Java, Ruby, Bash, TypeScript, HTML, JavaScript, Python, CSS, Elixir, PHP, GraphQL, Scala
  • Frameworks

    Django, Ruby on Rails (RoR), Spring, Spring Boot, MUI (Material UI), MUI CSS, Bootstrap, Flutter, React Native, Angular
  • Libraries/APIs

    Ruby on Rails API, React, Node.js, OpenAPI, Vue, QuickBooks API
  • Tools

    Git, Jira, Slack, Terraform, Google Compute Engine (GCE), Amazon EKS, RabbitMQ
  • Paradigms

    API Architecture, Test-driven Development (TDD), Unit Testing, Agile Project Management
  • Platforms

    Docker, MacOS, Amazon Web Services (AWS), Linux, Google Cloud Platform (GCP), Kubernetes, Firebase, Heroku
  • Storage

    MySQL, PostgreSQL, MongoDB, Google Cloud, Cloud Firestore
  • Industry Expertise

    Project Management
  • Other

    Software System Architecture Development, Technical Leadership, Software Development, Algorithms, APIs, Back-end, Back-end Development, Web Development, RESTful APIs, Integration Testing, Software Testing Automation Framework (STAF), UI, Full-stack, ESLint, Enterprise, Enterprise Systems, Software Architecture, GitFlow, Architecture, Computer Science, AWS, AWS RDS, Technical Program Management, Chrome Extensions, Team Leadership, Artificial Intelligence (AI), Computer Security, Statistical Analysis, Statistical Modeling, Interaction Design (IxD), Fintech, CTO

Education

  • Master's Degree in Computer Science
    2014 - 2015
    Columbia University - New York, NY, USA
  • Bachelor's Degree in Statistics
    2008 - 2012
    University of Iowa - Iowa City, IA, USA
  • Bachelor's Degree in Computer Science
    2008 - 2012
    University of Iowa - Iowa City, IA, USA

Certifications

  • Functional Programming Principles in Scala
    JULY 2020 - PRESENT
    Coursera
  • Deep Learning Specialization
    APRIL 2019 - PRESENT
    Coursera
  • Interaction Design Specialization
    OCTOBER 2017 - PRESENT
    Coursera

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