CaptionStack — Privacy Policy

CaptionStack is published by Marcio Koziel Software. It has no accounts, no analytics, no advertising, and no servers. Everything you do in the app happens on your iPhone. We have no way to see your videos, your captions, or even whether you use the app.

What CaptionStack stores, and where

When you import a video, CaptionStack copies it into its own storage on your iPhone along with a project file describing your captions, languages, and styling. This is what lets you close the app and pick a project back up later.

• Everything is written to your device's app storage only.
• Nothing is uploaded anywhere.
• Deleting a project removes its video and caption data from your device.
• Deleting the app removes all of it at once.

What we collect

Nothing. CaptionStack contains no analytics SDK, no crash reporter, no advertising identifier, and no tracking of any kind. We do not know who you are.

Permissions CaptionStack asks for

Each permission is used for exactly one thing, and only while you're using the app:

• Photos — to let you import a video you choose, and to save your finished subtitled video back to your library. CaptionStack never reads your library in the background and never uploads anything from it.
• Speech Recognition — to convert the audio in your imported video into text. On iOS 26 this runs on-device using Apple's downloaded speech model; your audio is not sent to Apple for recognition.

Apple system services

CaptionStack builds on two of Apple's on-device technologies. Both run locally, but each needs a one-time model download from Apple the first time you use it — the same way adding a new keyboard language does.

• Speech transcription uses Apple's on-device speech model for the language you pick. The model file is downloaded from Apple; your video and its audio are not.
• Translation uses Apple Intelligence's on-device language model. It must be enabled on your device. Your caption text is processed locally and is not sent to Apple.
• These downloads are handled by iOS itself and are covered by Apple's privacy policy, not ours. CaptionStack makes no network requests of its own.

Network use

CaptionStack itself never connects to the internet. The only network activity that can occur is iOS downloading the Apple model assets described above. Once those are present, the app works fully in airplane mode.

Children

CaptionStack is safe for all ages in the sense that it collects nothing from anyone. It is not directed at children specifically, and because no data is collected, no data about children is collected either.

Your control over your data

Because your data lives only on your iPhone, you are always in full control of it.

• Delete a single project from the project list to remove its video and captions.
• Delete the app to remove everything CaptionStack has stored.
• Revoke Photos or Speech Recognition access at any time in Settings ▸ CaptionStack.
• There is no account to close and no data for us to delete on your behalf, because we never had any.

Changes to this policy

If this policy ever changes, the updated version will be published at this address with a new date. Because the app collects nothing, we don't expect the substance to change.

Contact

Questions about privacy in CaptionStack can go to support@uzum.services.