Minimal Currency Converter

A Chrome extension for converting multiple currencies with real-time exchange rates and a minimalistic user interface.

Powered by real-time data from the European Central Bank and CoinGecko, the extension lets you effortlessly swap between dozens of world currencies — and even Bitcoin, Ethereum and other cryptocurrencies — right from your browser.

✨ Features

• Real-time exchange rates — rates are refreshed automatically every 15 minutes.
• Convert many currencies at once — add up to 15 currency rows and see them all update simultaneously.
• 38 currencies supported — 33 fiat currencies plus 5 cryptocurrencies.
• Sleek, minimal design — a clean, intuitive interface that stays out of your way.
• Privacy-friendly — only the storage permission is requested and no personal data is collected.
• Remembers your setup — your selected currencies and last entered value are saved locally.
• Open source — fully transparent and available on GitHub.

💱 Data sources

Type	Source
Fiat currencies	European Central Bank rates, served via the project's data/rates.json
Cryptocurrencies	CoinGecko API

🌍 Supported currencies

Fiat (33)

Code	Currency	Code	Currency	Code	Currency
USD	US Dollar	EUR	Euro	JPY	Japanese Yen
BGN	Bulgarian Lev	CZK	Czech Koruna	DKK	Danish Krone
GBP	Pound Sterling	HUF	Hungarian Forint	PLN	Polish Zloty
RON	Romanian Leu	SEK	Swedish Krona	CHF	Swiss Franc
ISK	Icelandic Krona	NOK	Norwegian Krone	HRK	Croatian Kuna
RUB	Russian Rouble	TRY	Turkish Lira	AUD	Australian Dollar
BRL	Brazilian Real	CAD	Canadian Dollar	CNY	Chinese Yuan
HKD	Hong Kong Dollar	IDR	Indonesian Rupiah	ILS	Israeli Shekel
INR	Indian Rupee	KRW	South Korean Won	MXN	Mexican Peso
MYR	Malaysian Ringgit	NZD	New Zealand Dollar	PHP	Philippine Peso
SGD	Singapore Dollar	THB	Thai Baht	ZAR	South African Rand

Cryptocurrencies (5)

Code	Currency
BTC	Bitcoin
ETH	Ethereum
USDT	Tether
XRP	XRP
BNB	Binance Coin

📦 Installation

From the Chrome Web Store (recommended)

Install directly from the Chrome Web Store.

Manual / developer install

1. Clone or download this repository.
2. Open chrome://extensions in Chrome.
3. Enable Developer mode (top-right toggle).
4. Click Load unpacked and select the src/ folder.
5. The extension icon will appear in your toolbar.

Requires Chrome 100 or newer.

⚙️ How it works

• The service worker (service_worker.js) fetches fiat rates from data/rates.json and crypto prices from CoinGecko, caches them in memory, and refreshes them every 15 minutes.
• The popup (popup.js) builds the currency rows and sends a convertValue message to the service worker whenever you type a value or change a currency.
• The service worker computes the conversion from the cached rates and returns the result, which the popup formats and displays.
• Your selected currencies and last value are persisted via localStorage so the popup reopens in the same state.

🤝 Contributing

Contributions are welcome! Feel free to open an issue or submit a pull request for bug fixes, new currencies, or improvements.

📄 License

Released under the MIT License. Copyright © 2020 Outis Nemo.