1st YearBeginnerWeb 1-2 weeks
Currency & Unit Converter with Live Rates
A converter app that handles live currency exchange rates from a public API plus offline unit conversions (length, weight, temperature), with a clean responsive UI.
HTMLCSSJavaScriptFetch APIExchangeRate API
Find GitHub repos & source code →How to build it — step by step
- 1Unit engine: Implement deterministic conversion factors for length, weight, and temperature offline.
- 2Currency API: Fetch live rates with fetch + async/await and cache the last response.
- 3UI: Build a two-field converter with a swap button and live recalculation on input.
- 4UX polish: Add recent conversions, favourite currency pairs, and graceful offline fallback to cached rates.
Key features to implement
- ✓Live currency rates
- ✓Offline unit conversions
- ✓Swap and reverse
- ✓Favourite pairs
- ✓Cached offline fallback
💡 Unique twist to stand out
Add a mini sparkline of the selected currency pair’s recent trend using a free historical-rates endpoint.
🎓 What you'll learn
API consumption, async/await, caching, numeric conversion logic, and responsive UI.