Build FX_CHECKER with Vanilla JavaScript
Build a real-world currency converter with Vanilla JavaScript, live exchange rates, historical data, Favorites, and local browser history.
FX_CHECKER is a single-page currency dashboard built with plain HTML, CSS, and JavaScript. The finished project lets a user convert currencies, browse market rates, search the rates table, save favorite pairs, review recent conversions, and inspect historical reference-rate trends.
Prerequisites
You should be comfortable with basic HTML elements, CSS selectors, JavaScript variables/functions, and opening a project in a browser. You do not need a framework for this course.
Why this project
The project is small enough to understand end-to-end but rich enough to exercise the parts of frontend JavaScript that matter in practical work: state, events, rendering, API requests, persistence, and a browser-native chart.
How the course works
You start from a prepared interface. Each implementation lesson changes one meaningful part of app.js, then gives you a concrete checkpoint to verify before continuing. The course follows the architecture already used by FX_CHECKER instead of introducing a framework or a new application pattern.
What you finish with
By the end, the starter interface has become the complete FX_CHECKER application, using the project’s live exchange-rate service, Frankfurter historical data, localStorage for Favorites/history, custom currency dropdowns, and a Canvas-based trend chart.
Course structure
The modules move from application state and navigation into converter behavior, market data, persistence, historical charting, and final validation. The focus stays on the next change the actual project needs.