Riffloop is an all-in-one music practice application that integrates with YouTube and supports uploaded audio files. Its primary function is to convert any song into a practice tool by enabling users to isolate individual instruments, loop specific sections, change the key, and adjust the playback speed without altering pitch. The tool operates as a browser extension and a web application, allowing users to work directly within the YouTube interface or use the standalone Studio for uploaded files. The application includes a stem splitter that separates a song into six distinct components: vocals, drums, bass, guitar, piano, and other elements. Users can solo or mute any of these stems to focus on a particular instrument or to create a backing track. Additional features include an A-B loop function that can cycle a selected region (up to 30 seconds in the free tier, longer in paid tiers), pitch shifting that transposes the entire track without a chipmunk effect, and tempo control that slows down or speeds up playback while preserving pitch. The free tier allows up to five stem separations per day, loops up to 30 seconds, and basic pitch and speed controls. The Pro tier removes these limits, provides longer loops, full-length song processing, higher quality separation, a saved loop library, and cross-device sync. Typical use cases include musicians learning a song by isolating a guitar riff or vocal line, singers practicing with a karaoke track by muting the original vocals, and instrumentalists working on difficult passages by looping a short section and gradually increasing tempo. The workflow typically begins with opening a YouTube video or uploading a file, then using the stem splitter to separate the track, selecting and looping a region, adjusting key and speed as needed, and practicing along with the modified audio. The tool is designed to run locally in the browser extension, meaning no files are uploaded to external servers for basic processing, though the full Studio may require processing on the web app. Technical requirements include a modern web browser with support for the Riffloop extension, and an internet connection to access YouTube videos. The application does not require plugins or additional software downloads. It is available on the Riffloop website, and users can start with a free account to access the basic features.