Slow Down Extension Privacy Policy

Last updated: October 20, 2026

Overview

The Slow Down extension, for Chrome, Firefox and Safari, lets you slow down, transpose and loop YouTube videos, and shift the pitch of audio while using the Slow Down music practice app. This policy explains how the extension handles your data.

Audio Capture

The extension uses Chrome's tabCapture API to capture audio from the current browser tab. It only captures audio on Slow Down domains (ralenty.com, slowdownpractice.com, slowdowntunes.com, slowdownvideos.com, slowdown.pro, slowdown.cloud, and localhost for development), and on a YouTube tab when you turn on transpose, fine tune, vocal reduction or volume in the side panel. Turning them back off hands the sound back to the tab. It does not capture audio from any other website, and audio captured on YouTube never leaves your browser.

Firefox and Safari don't capture the tab. There, the extension changes the YouTube video's own sound inside the page, with the Web Audio API, when you turn those settings on. That sound never leaves your browser either.

Audio Processing

Real-time audio features (pitch shifting, vocal separation) happen entirely within your browser using the Web Audio API. Captured tab audio is processed in real time and routed back to your speakers. It is never recorded or stored for these features.

Music Analysis

To detect BPM, musical key, and chords, the extension captures short snippets of tab audio (up to 180 seconds) and sends them to the Slow Down server for analysis. This happens only after you press "Analyze key, tempo and chords" on a Slow Down video page (until then the clips stay in your browser and are discarded), and never runs for a video whose analysis a rights holder has had removed (see Music Analysis & YouTube). This audio is:

  • Captured from the browser tab's audio output (not downloaded from any source)
  • Sent only to the Slow Down server, never to any third party
  • Used exclusively to extract musical metadata (BPM, key, chords)
  • Automatically deleted from the server immediately after analysis completes
  • Never stored, retained, or used for any other purpose

The detected metadata is saved to your Slow Down account to display on the video page.

Data Collection

The extension collects no data for itself. It stores on your device, with the browser's storage API, your sound settings for the tab you're on and, if you connect it to your Slow Down account, an access token for that account and your name to show you're connected.

On YouTube, the side panel changes the video's speed on your device. Once you connect it to Slow Down, it sends the Slow Down server the id of the YouTube video you have open, to say whether it's in your library, and saves to your account what you ask it to: adding the video, its speed and its markers. Nothing is sent before you connect, and you can disconnect from the panel or from your profile at any time.

Permissions Explained

  • activeTab: Required to initiate audio capture on the current tab (Chrome)
  • tabCapture: Captures the tab's audio for pitch processing (Chrome)
  • offscreen: Creates a background document for audio processing via Web Audio API (Chrome)
  • tabs: Checks whether a tab is a Slow Down or YouTube page, and stops processing when that tab closes or navigates away
  • storage: Remembers your sound settings and, once connected, your Slow Down access token on this device
  • sidePanel: Shows the Slow Down panel next to YouTube videos (Chrome; Firefox uses its sidebar, and Safari shows the panel in the YouTube page)
  • identity: Opens the Slow Down sign-in and Allow page when you connect the extension to your account (Chrome and Firefox; Safari opens it in a tab)
  • YouTube and Slow Down sites: Reads which YouTube video is playing and its time, sets its speed, and talks to your Slow Down account

Third-Party Services

The extension communicates only with the Slow Down server, for music analysis and, once connected, your library (as described above). It does not communicate with any other third-party services. It has no analytics and no tracking.

Contact

Questions about this privacy policy? Reach out at theo@theowecker.com.