Privacy Policy — CaptionUI
Last updated: October 2, 2026
Effective: October 2, 2026
Summary
CaptionUI transcribes, edits, styles and exports captions entirely on your iPhone. No server of ours receives your content, there are no user accounts, and we collect nothing. Your video, its audio and the transcript are never sent to us — there is nowhere to send them.
This document exists to say that precisely, including the parts where "nothing leaves the device" would be an oversimplification.
1. Who we are
CaptionUI is an iPhone app developed by Kingdom Ideas Factory LTDA (CNPJ 45.049.427/0001-12), based in Recife, Pernambuco, Brazil.
Contact: contato@kifactory.app.
2. We collect no data
We do not collect, receive or have access to any of your data. Concretely:
- There is no account. There is no sign-up, login, email or password anywhere in the app.
- No server of ours receives your content. The app has no back-end, sends nothing, and receives nothing about you. It makes one request of its own, and only when you ask: downloading the sync model (section 4d). It is a download of a public file; nothing goes up with it.
- There are no third-party SDKs. No analytics, tracking, attribution or crash-reporting library is included — no Firebase, no Crashlytics, no Sentry, no equivalent. The app has zero external dependencies.
- There is no tracking. The app's privacy manifest declares
NSPrivacyTracking = falseand no collected data types.
3. What happens to your video
When you import a video, CaptionUI makes a copy of it inside the app's private area on your iPhone, so the project keeps working if the original is deleted or offloaded to iCloud. That copy, the transcript, the styles and the captions stay in that private area, which only CaptionUI can see.
Transcription happens on the device. Speech recognition uses the system's on-device mode exclusively: the app requires local processing unconditionally, and when the language model is not installed it tells you and stops, instead of sending the audio to servers. Your audio is never transmitted. Caption translation, when used, works the same way.
4. What actually leaves the device
This is the part a generic text usually leaves out. None of what follows sends data to us — but all of it is real network traffic or a copy going off the device, and you deserve to know:
a) Language model downloads (Apple). The first time you transcribe or translate in a language whose model is not yet installed, the system downloads that model from Apple's servers. It is a download: none of your content goes up with it. The download is performed by the operating system, under Apple's privacy policy.
b) Purchases (Apple). If you subscribe to Pro, the purchase is handled entirely by Apple. CaptionUI does not see, ask for or store any payment data. The only record left on the device is a flag saying the subscription is active.
c) iOS backup. CaptionUI's projects live in the app area that iOS includes in the default backup. If you have iCloud Backup turned on, a copy of your imported videos and your transcripts may be sent to iCloud by the system, under Apple's privacy policy and your own settings. CaptionUI neither performs nor controls that upload — but saying "nothing leaves the device" without mentioning it would be inaccurate. You can turn off backup for the app in Settings › [your name] › iCloud › Manage Storage.
d) The sync model (optional). If you choose to download the model that sharpens karaoke caption timing, the app fetches that file — about 277 MB, which take up about 317 MB once unpacked — from a download server we operate (models.kifactory.app). It happens only if you tap “Download”: never alongside installing the app, never automatically, never in the background. The request carries none of your data: no body, no identifier, nothing about you or your videos. Like any web request, it shows that server your IP address. The file is checked against a SHA-256 checksum before it is used, and you can remove it afterwards in Settings › Models to reclaim the space. The app works without it — every caption style works, with word-level rather than syllable-level precision.
e) What you share yourself. Exported videos, caption files (SRT/VTT/ASS), style presets and the diagnostic log only leave the device when you use the share sheet or save to the Photo Library. You pick the destination, and the destination receives the file. If you save to the Photo Library and have iCloud Photos enabled, the video enters that sync.
5. Diagnostic log
CaptionUI keeps a local technical log so you can report problems. It is structurally incapable of containing what you said or wrote: the format has no free-text field. Each event carries only numbers, flags and fixed codes — for example, how many words were recognized, how long an export took, or an error code such as speech.assets_missing. There is no transcript, no file name, no path.
That log stays on your device and is never sent automatically. It only leaves if you tap "Share" on the Diagnostics screen and choose where to send it. You can delete it at any time with "Clear log", on the same screen.
6. Permissions
CaptionUI asks for two permissions, both only when they are needed:
- Speech recognition — to transcribe your video's audio on this device.
- Add to Photo Library — only to save the captioned video when you ask for it. It is an add permission, not a read one: the app has no access to your photos.
We do not ask for camera, microphone, location, contacts, or tracking permission.
7. Children
CaptionUI is not directed at children and collects no data from anyone, of any age.
8. Your rights (LGPD / GDPR)
Since we do not collect, store or process any of your personal data on our systems, there is no data of ours to access, correct, port or delete. The app's data stays on your device and under your control: deleting a project in the app, or uninstalling the app, removes it.
For the parts described in section 4 that are operated by Apple (model downloads, purchases, iCloud backup), Apple's privacy policy and controls apply.
9. Changes to this policy
If this policy changes, the "last updated" date above changes with it, and the new version becomes available at the same address and inside the app.