Web + Android app · September 2026 Live
CápsulasDev
A platform for learning to code in Spanish with 19 hands-on tracks, plus its Android app with Capi as your guide.
What it is
Nineteen tracks —from Python and SQL to Docker, React or accessibility— with exercises you solve in the browser, levels that unlock and mini exams with explanations.
The Android app puts the experience in your pocket: playable capsules, spaced review, trophies and all your progress saved offline.
What I built
- 950 exercises, each with an explanation, a mission, three hints and three checks
- In-browser labs: Markdown with CommonMark, accessibility with DOMParser and automated testing
- Accounts with email codes and progress sync (Supabase)
- App built with Expo and React Native: onboarding with Capi, a daily plan, XP and thirteen trophies
- Offline progress in SQLite and review at 1, 3 and 7 days
The hard parts
Testing the tests
In the testing lab, the student’s tests must pass against the correct implementation and catch 19 faulty variants, cross-checked with node:assert.
Python without running code
The app ships an educational interpreter with phone-friendly limits: you learn Python offline without running arbitrary code on the phone.
Two repositories, one contract
The website is the backend’s source of truth; the app lives separately so signing secrets, dependencies and deployments never mix.