Marshall Shen
Verified Expert in Engineering
Full-stack Developer
Berwyn, IL, United States
Toptal member since September 13, 2022
Marshall is an accomplished technical leader with a strong background in building AI software and leading engineering teams. He has delivered innovative solutions for tech companies of all sizes in fintech and healthcare. With over three years of experience running startups, Marshall has led engineering teams of over 20 people, including offshore teams in China.
Portfolio
Experience
- Ruby on Rails API - 12 years
- API Architecture - 10 years
- Software System Architecture Development - 10 years
- Python 3 - 10 years
- React - 7 years
- Django - 6 years
- Technical Leadership - 5 years
- Artificial Intelligence (AI) - 5 years
Preferred Environment
MacOS
The most amazing...
...thing I've built was a virtual education classroom product that supports more than 100,000 virtual classrooms per day.
Work Experience
Lead Software Engineer
Triumph Financial
- Led the design and implementation of invoice auditing automation for LTL payments, reducing manual review effort for brokers while improving audit accuracy and processing speed.
- Architected and evolved high-throughput Rails and PostgreSQL systems handling large-volume EDI-210 invoice data, ensuring reliability and performance for enterprise freight customers.
- Designed and shipped internal automation features that enabled brokers to operationalize complex audit workflows, increasing feature adoption and measurable efficiency gains.
Web Full-stack Developer (via Toptal)
Ashleigh Tatiana Aston
- Developed a social media platform for digital publishers with OpenAI integration.
- Migrated the old data from the legacy media site to the new publishing site.
- Built a full-stack web app from scratch using Ruby on Rails and React/TypeScript deployed on Google Cloud Platform.
Senior Staff Software Engineer
PayPal
- Led the development and operation of Braintree’s core payment platform, processing over $1 billion in daily transaction volume in partnership with major banking partners including Wells Fargo.
- Architected and scaled Venmo consumer systems supporting 1+ million daily active users, ensuring high availability, performance, and regulatory compliance at scale.
- Led and coordinated a 40-person cross-functional front-end and back-end engineering organization to ship and iterate on Venmo credit card and debit card products from launch through growth.
Technical Architect (via Toptal)
Reflik Inc
- Led the architecture of Reflik's new AI-based talent marketplace. Built the foundational infrastructure on AWS using Kubernetes, Python Django, and React, with GitHub Actions for the CI/CD pipeline.
- Trained the development team in India to use the foundational infrastructure.
- Worked with business leaders to finalize their two-year product roadmap.
API Developer (via Toptal)
Shearwater Health Inc
- Worked with the executive to refine the data pipeline using Microsoft Power BI and Microsoft Azure.
- Automated the nurse staffing data pipeline using Ruby on Rails and Microsoft Azure.
- Trained the staff to be self-sufficient and operate the data pipeline themselves.
Fractional CTO
HiLink
- Provided technical vision to transition the company to a platform-as-a-service (PaaS) business.
- Managed a remote engineering team of 12 in China.
- Helped the company win enterprise customers and secure the first few enterprise contracts, which would help the company secure additional venture capital funding.
AWS Architect
One Step Holdings LLC
- Consulted with clients to determine their business needs.
- Developed software designs using AWS to meet those needs.
- Created a Python/Docker codebase that lets clients quickly begin product development.
Senior Developer
Therapy App LLC
- Built expert HIPAA-compliant data pipelines for personal patient data.
- Served 40+ mental health clinics across the US, providing practical solutions tailored to each client's needs.
- Delivered requested patient information within tight timelines without sacrificing quality.
Senior Software Engineer
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.
Software Engineer
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.
Experience
CardJoy
Education
Master's Degree in Computer Science
Columbia University - New York, NY, USA
Bachelor's Degree in Statistics
University of Iowa - Iowa City, IA, USA
Bachelor's Degree in Computer Science
University of Iowa - Iowa City, IA, USA
Certifications
Functional Programming Principles in Scala
Coursera
Deep Learning Specialization
Coursera
Interaction Design Specialization
Coursera
Skills
Libraries/APIs
Ruby on Rails API, React, REST APIs, Node.js, OpenAPI, Vue, QuickBooks API, PyTorch
Tools
Git, Jira, Slack, Terraform, Google Compute Engine (GCE), Amazon EKS, RabbitMQ, Cron
Languages
Python 3, Java, Ruby, Bash, TypeScript, HTML, JavaScript, Python, CSS, Elixir, PHP, GraphQL, Scala, SQL, Go
Frameworks
Django, Ruby on Rails (RoR), Spring, Spring Boot, Material UI, MUI CSS, Bootstrap, Tailwind CSS, Flutter, React Native, Angular, Laravel
Paradigms
API Architecture, Test-driven Development (TDD), Unit Testing, Agile Project Management, Role-based Access Control (RBAC), Automation, Microservices, Web Architecture, Management
Platforms
Docker, MacOS, Amazon Web Services (AWS), Linux, Google Cloud Platform (GCP), Kubernetes, Firebase, Heroku
Storage
MySQL, PostgreSQL, Databases, Data Pipelines, MongoDB, Google Cloud, Cloud Firestore, JSON, Company Databases
Industry Expertise
Project Management
Other
Software System Architecture Development, Technical Leadership, Software Development, Algorithms, APIs, Back-end, Back-end Development, Web Development, Integration Testing, Software Testing Automation Framework (STAF), User Interface (UI), Full-stack, ESLint, Enterprise, Enterprise Systems, Software Architecture, GitFlow, Architecture, API Integration, Multi-tenant Architecture, Computer Science, Amazon RDS, Technical Program Management, Chrome Extensions, Team Leadership, Large Language Models (LLMs), Artificial Intelligence (AI), Computer Security, Statistical Analysis, Statistical Modeling, Interaction Design (IxD), Fintech, CTO, Technical Project Management, AWS Certified Developer, CSV, Machine Learning, Non-performing Loans (NPL), Cloud, Cloud Services
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