This Firefox extension adds a button to your Firefox toolbar. When you click on it, it opens a simple popup displaying the latest info about the stocks you follow.
Followed stocks are set in the extension's options page.
Stock data is refreshed each time you open the popup. It requires a Financial Modeling Prep API Key.
The API also supports Forex (e.g. USDEUR) and Crypto (e.g. BTCUSD) data.
Popup code originally inspired by https://github.com/toddwschneider/stocks.