Founder & engineer · 2024
Lexicon
An interactive platform for learning to program in the browser — real code execution, instant feedback, and a curriculum that respects the learner.
- Astro
- TypeScript
- PostgreSQL
- WebAssembly
- Stripe
- 12,400
- Learners
- 73%
- Completion
- 240
- Lessons
The brief
I teach programming, and I kept hitting the same wall: tooling that got in the way of the idea. Lexicon is the platform I wished I could hand a beginner — open a lesson, write real code, run it in the browser, see what happened.
What I built
A WebAssembly runtime executes learner code client-side, so there is no server round-trip and no sandbox to provision per student. Around it sits a spaced curriculum, progress tracking on Postgres, and Stripe for cohorts.
- In-browser execution — a WASM toolchain compiles and runs submissions locally, with deterministic test harnesses per exercise.
- Pedagogy first — lessons are authored as content, reviewed like prose, and versioned in git.
- Calm UI — typography-led, distraction-free, readable at every breakpoint.
Outcome
Over twelve thousand learners, a 73% lesson-completion rate well above category norms, and a curriculum that other educators now contribute to.