Summary

  • Your microphone audio is transcribed on your computer. It is not uploaded.
  • Transcripts are saved in this browser only. You can delete them at any time.
  • No account, no analytics, no advertising, no tracking of any kind.
  • The only network request the extension makes is the one time download of the speech model files.
  • Captions drawn on a web page can be read by that page. By default they go only to the tab you choose.

What the extension processes

Microphone audio

  • What: sound from the microphone you pick, captured only while you press Start and until you press Stop.
  • How: a voice activity gate decides which 32 ms frames contain speech, and a speech model turns those frames into text. Both run inside the extension on your own computer.
  • Where it goes: nowhere. Audio is held in memory while you record and is discarded when the session ends. No audio is written to disk and none is sent to us or to anyone else.

Transcript text

  • What: the words the model recognised, with the time each line started and finished.
  • Where stored: locally in this browser, in Chrome extension storage. The list keeps the newest 20 sessions and up to 400 lines per session.
  • Exports: saving a session as a text or subtitle file writes that file to your own Downloads folder. Nothing is sent anywhere.

Settings

  • What: the model size you picked, the microphone you picked, where captions open, the caption text size, and where you last dragged the caption strip.
  • Where stored: locally in Chrome extension storage. These values never leave your browser.

Network requests

The extension makes exactly one kind of network request. On first use it downloads the speech model files from download.moonshine.ai, the model publisher. The tiny model is about 43 MB, and the larger options are larger. That request carries no audio, no transcript and no personal information. The files are then cached by your browser, so the extension works offline afterwards.

There is no other traffic. Fonts are packaged inside the extension, not loaded from a font service. There is no analytics, no crash reporting, no remote configuration and no advertising identifier.

Where captions appear, and who can see them

Captions are drawn inside the web page you are on, so that they stay visible while you present. That has a consequence worth stating plainly: text drawn on a page can be read by that page. The caption strip lives in a closed shadow root, which makes casual inspection harder, but it is not a security boundary and this policy does not pretend it is.

  • One tab, chosen by you: captions go only to the tab you invoked the extension on, by clicking its icon or pressing its shortcut on that page.
  • No broad access: the extension holds no permission for websites in general. Chrome grants it that single tab when you invoke it, and withdraws the grant when the tab navigates or closes.
  • Floating window: the always on top window belongs to the extension and is not a web page.

What we do not collect

  • No audio recordings, ever.
  • No transcripts on any server. There is no server for them to reach.
  • No name, email address or account, because there is no sign in.
  • No browsing history, page contents or URL is sent to us.
  • No analytics, telemetry, crash reports or advertising identifiers.
  • No location data.
  • Nothing is sold, rented or shared with data brokers, and there are no third party ad networks.

Storage and retention

Everything Captioncast keeps lives in Chrome extension storage on your device. Nothing expires on a server because nothing is on a server. On your side:

  • The newest 20 sessions are kept, up to 400 lines each.
  • Delete removes one session. Clear all removes every session, after a second click.
  • Removing the extension deletes its storage, including all saved transcripts.
  • Uninstalling also removes the cached model files from your browser profile.

Permissions and why

  • storage: save your settings and your transcripts locally.
  • activeTab: access to the one tab you invoke the extension on, granted by Chrome when you click the toolbar icon or press the shortcut. Nothing else is readable.
  • scripting: inject the caption strip into that tab. There are no content scripts declared for all sites.
  • sidePanel: open the control surface in Chrome's side panel when you prefer that to a separate window.
  • https://download.moonshine.ai/*: fetch the speech model files once.
  • The caption strip only ever runs on the tab you invoked the extension on. If you navigate that tab, the strip stops until you invoke the extension again.
  • Microphone: Chrome asks for your permission the first time you press Start. This is not a manifest permission and you can revoke it at any time in Chrome's site settings.

Third parties

  • Moonshine AI publishes the speech model. Your browser downloads the model files from their server. They do not receive your audio or your transcripts.
  • Chrome Web Store distributes the extension and handles installs and updates under Google's own privacy policy.
  • No other company is involved, and no data is sold or shared for advertising.

Children

Captioncast is a presentation tool for general use. It is not directed at children, and because it collects nothing there is nothing to delete if a child uses it.

Changes to this policy

If a future version of the extension changes what it handles, this page will be updated before that version is published, and the effective date above will change. Material changes will also be described in the extension's release notes on the Chrome Web Store.

Contact

Questions about this policy, or about anything the extension does, go to contact@polarislabs.pk. The same address is in the extension under Options, Contact.