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Hi, I'm William Song, a full-stack engineer with over 10 years of experience building web and mobile applications across finance, healthcare, and e-commerce domains. I thrive in fast-moving startup environments where I get to own projects end-to-end and collaborate closely with cross-functional teams. I enjoy tackling complex problems and building scalable solutions using modern technologies like React, Node.js, and AWS. I also bring solid DevOps skills and love mentoring junior engineers to help grow strong technical teams.…Hi, I'm William Song, a full-stack engineer with over 10 years of experience building web and mobile applications across finance, healthcare, and e-commerce domains. I thrive in fast-moving startup environments where I get to own projects end-to-end and collaborate closely with cross-functional teams. I enjoy tackling complex problems and building scalable solutions using modern technologies like React, Node.js, and AWS. I also bring solid DevOps skills and love mentoring junior engineers to help grow strong technical teams.

William Song

Developer, Full Stack Developer, Front-End Developer, +2

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Hi, I'm William Song, a full-stack engineer with over 10 years of experience building web and mobile applications across finance, healthcare, and e-commerce domains. I thrive in fast-moving startup environments where I get to own projects end-to-end and collaborate closely with cross-functional teams. I enjoy tackling complex problems and building scalable solutions using modern technologies like React, Node.js, and AWS. I also bring solid DevOps skills and love mentoring junior engineers to help grow strong technical teams.…Hi, I'm William Song, a full-stack engineer with over 10 years of experience building web and mobile applications across finance, healthcare, and e-commerce domains. I thrive in fast-moving startup environments where I get to own projects end-to-end and collaborate closely with cross-functional teams. I enjoy tackling complex problems and building scalable solutions using modern technologies like React, Node.js, and AWS. I also bring solid DevOps skills and love mentoring junior engineers to help grow strong technical teams.

Available to hire

Hi, I’m William Song, a full-stack engineer with over 10 years of experience building web and mobile applications across finance, healthcare, and e-commerce domains. I thrive in fast-moving startup environments where I get to own projects end-to-end and collaborate closely with cross-functional teams.

I enjoy tackling complex problems and building scalable solutions using modern technologies like React, Node.js, and AWS. I also bring solid DevOps skills and love mentoring junior engineers to help grow strong technical teams.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Intermediate

Intermediate

Language

English

Fluent

Work Experience

Senior Software Engineer at DollyCard

April 1, 2023 - Present

Developed and maintained full-stack features across web and mobile using React, React Native, Redux, TypeScript, Node.js, Django, and other technologies for fintech expense and payment tools. Integrated payment SDKs like Stripe and PayPal, led design of an internal CRM system, and shipped features with short cycles using feature flags and staged rollouts. Built finance dashboards and export tools, set up automated testing, managed infrastructure using Docker and AWS, and built CI/CD pipelines. Mentored junior engineers and collaborated with founders and customers to shape product direction.

Senior Software Engineer at WeMoney

April 1, 2023 - July 31, 2025

Built and maintained core features for a finance app using Next.js, TailwindCSS, TypeScript, Node.js, AWS RDS and Elasticsearch. Improved mobile performance with React Native bridge, automated testing strategy across multiple layers, and maintained CI/CD pipelines integrated with Firebase and AWS. Led legacy code refactor initiatives, built internal tools and admin dashboards for operations teams, contributed to hiring and mentoring, sprint planning, and feature delivery.

Software Engineer at Appello Software

April 1, 2018 - July 31, 2025

Developed products for healthcare and finance clients, implementing responsive design and enhancing user interfaces with React, Next.js, Angular, Tailwind CSS, and TypeScript. Designed scalable APIs with GraphQL, REST, Node.js, Nest.js, and databases including MongoDB and MySQL. Developed interactive 3D model app using Three.js and Babylon.js, used WebRTC and WebSocket for real-time communication, wrote clean code refactoring existing projects, and communicated frequently with clients regarding sprint stories and project status.

Software Engineer Intern at Appello Software

December 1, 2014 - July 31, 2025

Collaborated on implementing a new web feature for a subscription service using HTML, CSS, and JavaScript. Implemented Amplitude dashboard for behavioral metrics, contributed to feature enhancements and bug fixes, improved user experience by enhancing debug ability and workflow, practiced best development practices including code reviews and distributed development.