HD Quality Toggle for YouTube is a Firefox extension designed to enhance the video playback experience by allowing users to set their preferred video quality automatically. This tool is particularly useful for those who want to consistently watch videos in high definition, as it enables users to select from various resolutions including 4K, 1440p, 1080p, and more. By default, the extension plays videos in the highest available resolution, but users can easily adjust this setting according to their preferences.

The extension operates on a subscription-based model after a 30-day trial period. Users only need to sign in with their Google account to track the trial and manage payments. Notably, the extension does not collect personal data beyond email addresses, ensuring a level of privacy for its users. While the extension utilizes the YouTube API, it is important to note that it is not officially endorsed by YouTube or Google.