Sung Guk “John” Lee

An AI app for practicing spoken English. Students record a response, and the app transcribes it, checks whether it answers the prompt and uses the target pattern, then gives pronunciation feedback. I built it to replace the speech recordings I used to assign and collect one student at a time.

The app runs on Next.js App Router with React Server Components and Server Actions, backed by Supabase/PostgreSQL with versioned SQL migrations. Separate authentication flows for teachers and students are enforced with row-level security. Azure Speech handles phoneme analysis, OpenAI handles evaluation and moderation, Vercel cron jobs run scheduled work, and a content-addressed TTS cache keeps paid API costs down.

Backed by 1,200+ automated tests, including Playwright end-to-end coverage.

A role-based ticketing system for university support workflows, with separate dashboards and ticket queues for student, staff, and manager roles. Includes category-based routing, activity logs, a notification panel, and an automated pytest suite.

Primary contributor on a five-person team, authoring the majority of the backend and automated test suite.

A web app for keeping track of songs I want to learn on guitar. It stores the tuning, capo position, and a YouTube link for each one, plus how far along I am. Search and filter the library, or export the entire collection to JSON and import it again.