About
I'm William Lei, a software engineer based in Hong Kong. I studied Financial Technology at The Chinese University of Hong Kong, with a second major in Artificial Intelligence.
For two years I was the main developer of FinFAST.ai, an economic research platform, where I worked across the whole product: data pipelines, retrieval, AI features, the web app, and its deployment on AWS and Azure. I also mentored and coordinated a team of ten interns, including training them to review and test AI-generated code.
I now take on freelance projects where that whole-path experience helps: when the data, the AI and the app all have to work together, and work fast.
How I work
Measure first
I find out where the time and money actually go before changing anything, and report the result in the same numbers.
Small, working steps
You see working software early and every week, not a big reveal at the end.
Code your team can own
Readable, tested and documented, because you'll be running it long after I've handed it over.
Skills
- Languages
- Python, TypeScript, JavaScript, SQL, Java, C++, Stan
- Web
- Next.js, React, REST APIs, Google OAuth
- Data and AI
- MongoDB, data pipelines, RAG and LLMs, multi-agent systems, statistical and forecasting models, backtesting
- Cloud
- AWS (Amplify, CloudFront, API Gateway, Lambda, EC2, DynamoDB, RDS), Azure (AI Foundry, Cosmos DB, CI/CD)
Want to work together?
Book a 20-minute intro call, or write to william@wlei.org.