Font System Detector is a free Chrome extension designed for web developers and designers. This tool scans any webpage to identify and display all font combinations used, including details such as font family, size, weight, and line-height. The extension provides an organized view of fonts, allowing users to see them grouped by family, sorted by size and weight within a collapsible panel, making it easy to track font usage across a site.

The extension features a single hover mode, which highlights the specific element being hovered over, showcasing its font properties. Alternatively, the group hover mode highlights all elements that share the same font properties. Additionally, it checks font availability on popular platforms like Google Fonts and Adobe Fonts, providing quick access links for further exploration. This tool requires Chrome version 114 or higher to utilize the Side Panel API.