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Woonchan Cho
Verified Expert in Engineering
Software Developer
Seoul, South Korea
Toptal member since May 16, 2022
Bio
Woonchan is a self-motivated full-stack developer and data analyst with over 10 years of experience managing, developing, and maintaining various systems using React, Java, Spring, and Node.js. He is swift in adapting to different roles and new settings and handles vague requirements precisely.
Portfolio
Washington University in St. Louis
TypeScript, JavaScript, Java, Spring, Node.js, Python, APIs, Firebase Web SDK...
socialprove.com
TypeScript, Firebase Web SDK, Cloud Firestore, Firebase Cloud Functions, Vue...
Global Innovation Project
JavaScript, Amazon Web Services (AWS), Java, Front-end, Databases...
Experience
- Java - 9 years
- Spring - 5 years
- React - 5 years
- Firebase Web SDK - 5 years
- MongoDB - 5 years
- Node.js - 5 years
- TypeScript - 4 years
Preferred Environment
Node.js, Java, .NET, C#, ASP.NET, TypeScript, React
The most amazing...
...projects I've recently worked on are related to improving XNAT, the number one open-source medical image platform in the area, using React, Java, and Node.js.
Work Experience
Software Developer and Database Analyst
2017 - 2022
Washington University in St. Louis
- Built the React-based multi-platform application for web and desktop. Waiting for FDA approval to enable radiologists to quickly evaluate and annotate the medical images.
- Created Java Spring MVC and Python 3.x applications to construct the fully automated ETL, including extract, transform, and load process for importing medical images and reports to XNAT, a medical imaging informatics platform.
- Designed and developed the workflow engine to orchestrate, schedule, and monitor the state of the activities in the imaging informatics software platform named XNAT.
- Developed the HL7, the messaging standard for text-based clinical data, interface engine on top of the Spring MVC-based application.
- Designed and developed the data analytic tool to extract key startup success factors and metrics from founder surveys and other resources like web and front-end applications to help early-stage entrepreneurs make data-driven decisions.
Technologies: TypeScript, JavaScript, Java, Spring, Node.js, Python, APIs, Firebase Web SDK, Firebase Authentication, Cloud Firestore, MongoDB, Firebase, PostgreSQL, Scrum, Architecture, HTML5, Full-stack, Figma, User Interface (UI), User Experience (UX), HTML, Express.js, React Hooks, CSS, Firebase Cloud Functions, REST APIs, Git, Functional Programming, Amazon Web Services (AWS), Dynamics CRM 365, Microsoft Dynamics CRM, Front-end, React, Redux, Databases, HIPAA Compliance, GitHub, Spring Boot, Oracle, PL/SQL, SQL Stored Procedures, MongoDB Atlas, React Native, JSON, Data Feeds, DevOps, CI/CD Pipelines, NoSQL, Amazon EC2, Docker, NGINX, OAuth, OpenID Connect (OIDC), Redis, React Redux, JSX, Automated Testing, NPM, Cloud, Hibernate, Object-oriented Design (OOD), Microservices, Microservices Architecture, Camunda BPM, Multithreading
CTO and Full-stack Developer
2018 - 2018
socialprove.com
- Developed a React and Node.js-based marketing web app that helps increase a website's credibility and sales using social proof.
- Minimized the Firebase cloud service charges by optimizing the interactions with the server-side.
- Oversaw the development, the launch process, and the email marketing implementation, resulting in over 1,000 active users in a month.
Technologies: TypeScript, Firebase Web SDK, Cloud Firestore, Firebase Cloud Functions, Vue, Front-end, BigCommerce, React, Databases, User Interface (UI), JSON, DevOps, CI/CD Pipelines, NoSQL, Amazon EC2, OAuth, OpenID Connect (OIDC), React Redux, JSX, Cloud, Object-oriented Design (OOD)
Full-stack Developer
2017 - 2017
Global Innovation Project
- Developed the education portal that enables universities to provide resources related to leadership and communication.
- Used jQuery to develop the front-end UI and Java Spring to implement the back-end REST APIs.
- Directly communicated with the product manager and translated the verbal and written requirements to the real product.
Technologies: JavaScript, Amazon Web Services (AWS), Java, Front-end, Databases, Active Server Pages (ASP), User Interface (UI), Spring Boot, MongoDB Atlas, DevOps, CI/CD Pipelines, NoSQL, Amazon EC2, OAuth, OpenID Connect (OIDC), C#, .NET, Cloud, Object-oriented Design (OOD)
Senior Application Developer | Associate
2013 - 2014
JPMorgan Chase
- Managed the development of a localized online banking system and the interbank fund transfer system.
- Project-managed onshore and offshore cash management system implementations, including online banking and ACH payments, and guided local teams in using newly implemented global initiatives and applications.
- Headed the regulatory IT audit project to ensure the corrective action plans for previous findings were in place and developed automated audit check-up tools to drive gains in data accuracy and work-group efficiency.
- Coordinated and led local cash products, receivables, and payables overview sessions and advised the functional business development team on the roadmap for rolling out new cash management products for the next three years.
Technologies: Java, Data Analysis, JavaScript, Fintech, HTML, CSS, MySQL, Payment Processing, Front-end, Databases, Oracle, Socket Programming, Data Feeds, Object-oriented Design (OOD), Multithreading
Application Developer | Associate Manager
2008 - 2013
Citibank
- Designed and developed payments and collection products, including same-day bulk transfer, real-time direct deposit, electronic promissory note issuance service, and sweep account service. Acquired more than 100 corporate customers.
- Refactored and modernized the legacy codebase of the COBOL-based fund transfer system, improving the capacity of the daily transactions by 2X. Honored Citibank's CAO award in recognition of outstanding achievement for this work.
- Implemented various systems to transmit online transactions between the core deposit system and external organizations using multiple external organizations via different interbank protocols, including SWIFT and private data transfer.
Technologies: Java, COBOL, JavaScript, Pro*C, C++, Fintech, HTML, MySQL, Payment Processing, Front-end, Active Server Pages (ASP), Oracle, PL/SQL, SQL Stored Procedures, Socket Programming, Data Feeds, C#, .NET, Object-oriented Design (OOD), Multithreading
Full-stack Developer
2004 - 2005
Bit Computer
- Developed a paid SaaS service that provides drug information to doctors and pharmacists.
- Optimized the SQL queries to minimize the loading time of the website.
- Provided a consultation about the operation of the website to BAU people.
Technologies: ASP.NET, JavaScript, SQL, MySQL, Front-end, BigCommerce, Active Server Pages (ASP), PL/SQL, SQL Stored Procedures, C#, .NET, Object-oriented Design (OOD)
Experience
Online Education Website
A React and Firebase-based online education website. I was the full-stack developer that built a customer-facing education website and the content generation UIs for content providers. The website provides features for users to easily learn content, including memory cards and monthly quizzes. For fast content generation, it provides a conversion tool to translate markdown files to user-friendly formatted HTMLs.
Medical Image Reader and Annotator
A React-based multi-platform application for web and desktop that enables doctors and researchers to evaluate and annotate medical images and collect training data for machine learning uniformly.
The application is waiting for FDA approval. I closely worked with developers from NVIDIA to launch it on the NVIDIA Clara platform, which is its healthcare application framework for AI-powered imaging, genomics, and the development and deployment of smart sensors.
The application is waiting for FDA approval. I closely worked with developers from NVIDIA to launch it on the NVIDIA Clara platform, which is its healthcare application framework for AI-powered imaging, genomics, and the development and deployment of smart sensors.
Cryptocurrency (Blockchain) Arbitrage Platform
An AI-based cryptocurrency arbitrage platform that automatically detects arbitrage opportunities and performs transactions in milliseconds. For better performance, the core logic was implemented using C++.
A Startup Valuation App for VCs
An online-based smart tool calculates startup companies' valuation and risk of failure, collects historical startup data, extracts key success factors, and eventually helps the startup ecosystem grow by encouraging them to find better startup companies early.
Education
2015 - 2017
Master's Degree in Business Administration (MBA)
Washington University in St. Louis - St. Louis, Missouri, USA
2000 - 2008
Bachelor's Degree in Computer Science
Yonsei University - Seoul, South Korea
Certifications
JANUARY 2017 - PRESENT
Scrum Master
Scrum.org
DECEMBER 2016 - DECEMBER 2019
Project Management Professional (PMP)
Project Management Institute
Skills
Libraries/APIs
Node.js, React, React Redux, Firebase Web SDK, REST APIs, Stripe, Vue, jQuery, Web3.js
Tools
GitHub, JSX, NPM, Firebase Authentication, Git, MongoDB Atlas, Figma, Microsoft Dynamics CRM, NGINX, Camunda BPM
Languages
Java, JavaScript, TypeScript, HTML, CSS, COBOL, Python, HTML5, SQL, Active Server Pages (ASP), C#, Pro*C, C++, GraphQL
Frameworks
Spring Boot, Hibernate, Spring, Redux, .NET, Express.js, ASP.NET, React Native
Paradigms
HIPAA Compliance, Object-oriented Design (OOD), Functional Programming, DevOps, Automated Testing, Microservices, Microservices Architecture, Scrum, Socket Programming
Platforms
Web, Amazon EC2, Firebase, Blockchain, Oracle, Docker, Azure, Amazon Web Services (AWS), BigCommerce, Google Cloud Platform (GCP)
Storage
Databases, JSON, NoSQL, MongoDB, Cloud Firestore, PostgreSQL, MySQL, PL/SQL, SQL Stored Procedures, Google Cloud, Redis
Other
Software Development, APIs, Full-stack, User Interface (UI), Payment Processing, Front-end, Data Feeds, Cloud, Data Analysis, Architecture, Fintech, React Hooks, Firebase Cloud Functions, CI/CD Pipelines, OAuth, OpenID Connect (OIDC), Multithreading, Leadership, Finance, General Management, IT Project Management, Scrum Master, User Experience (UX), Springbot, Dynamics CRM 365, WebSockets
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