Privacy Policy

Last updated: 16 September 2026

Subline is an iOS app that adds captions to video on your device. This policy explains what data the app and its supporting services collect, what we do with it, and what we don't.

What we collect

• An install identifier. When you launch Subline for the first time, the app generates a random UUID and stores it on your device. We use it to track your subscription status and trial period server-side. It is not tied to your Apple ID, name, email, or any other personal identifier.
• Subscription transaction IDs. When you purchase a subscription, Apple gives us a signed transaction that we verify and store so we can tell whether you're a paying subscriber on server-backed features.
• Audio from videos you caption with cloud transcription. If you choose a cloud transcription provider (Pro or an active trial), the audio track from your video is uploaded to our servers, forwarded to a transcription provider, and kept briefly for processing and recovery as described below. On the on-device path, audio stays on your phone.
• Caption remix prompts. When you use the AI caption remix feature, the text of your captions and a single still frame from your video, together with your design prompt and project settings, are sent through Cloudflare to Google Gemini to create the design.

Caption editing, translation and Auto Clip

Cloud editing sends caption text, project settings, your instruction and recent editing instructions through Cloudflare to Google Gemini. Caption translation sends text and timing to Subline; caption text is then sent to Google Gemini for translation. Auto Clip sends timed caption text to Google Gemini to suggest clip boundaries. These features do not upload your video or microphone audio.

Which features use the cloud depends on your plan, and the app says so where you choose them: the Free plan transcribes on your iPhone, and Pro adds cloud transcription, Vibe designs, translation, cloud editing and Auto Clip. Settings → Privacy → Cloud AI & data use links to this policy, which names each provider and what it receives. Manual editing and on-device features never send your content anywhere.

On-device features

On-device transcription, supported on-device caption editing, microphone dictation and audio cleanup process your audio or text on your device. Some features download model files on first use: the transcription model your iPhone can run (480 to 626 MB, chosen by device model) and audio-cleanup models, hosted by Hugging Face. A download is an ordinary web request, so Hugging Face sees your IP address like any website; it never receives your audio, captions or video. Your chosen spoken language and the model choice are stored on your device only. If an edit needs a cloud fallback, the text of that edit goes to the cloud editing provider described above.

Saved projects, imported media, fonts, caption templates and translated language versions are stored on your device. Device backups may include this data according to your Apple backup settings. Delete a project in the app to remove its saved project files.

What we don't collect

• We don't ask for an account, email, name, or phone number.
• We don't use third-party analytics, advertising SDKs, or cross-site tracking.
• The app does not access your photo library outside of the specific videos and images you choose to import.
• We do not sell or share your data with third parties beyond the subprocessors listed below.

Subprocessors

We use the following services to operate Subline:

• Apple Inc.: App Store distribution, StoreKit subscription processing.
• Cloudflare, Inc.: hosting for our worker, a D1 database for install, grant and subscription records, R2 for short-lived audio uploads and encrypted backups, and durable objects for transcription sessions.
• KLIPY (KIKLIKO, Inc.): GIF search. When you search for a GIF in the app, the search text is sent through our worker to KLIPY, which returns matching clips. KLIPY does not receive your install ID or IP address, and we do not keep your searches.
• Deepgram, Inc.: optional cloud transcription.
• ElevenLabs, Inc.: optional cloud transcription.
• Google LLC (Gemini API): AI caption remix and cloud caption editing, translation and Auto Clip suggestions.
• Hugging Face, Inc.: hosting for downloadable on-device model files. Downloads involve normal network connection information; Subline does not send your recordings to Hugging Face.

Retention

• Audio uploaded for cloud transcription is retained only briefly while the transcription job runs and for recovery if the app is backgrounded or reconnects. Audio and cached transcription results are deleted automatically, typically within one hour after completion.
• Your install record (install UUID, first-seen timestamp, device attestation key, subscription links, any support grant and daily usage counters) is kept while your install is active. You can delete the server data for this install from Settings → Privacy → Delete my data. Deletion immediately revokes the install's credentials and removes its key, subscription links, grants and counters. The install UUID and first-seen timestamp alone are retained for up to approximately 13 months afterwards so that deleting and re-registering cannot restart a free trial; they identify no person. App Store subscriptions are managed separately.
• Subscription transaction IDs and App Store Server Notification records are kept for up to approximately 13 months after the subscription ends so we can verify renewals, honour refunds and prevent fraud. A nightly job enforces these windows and exports an encrypted-at-rest backup of the records above to private storage, retained for 35 days, so that a paying subscriber's access can be restored after an outage.

Subline does not store cloud editing, translation or design request bodies as saved projects on its servers. Operational records may include request status, timing, usage counts and the install identifier. AI providers may handle request data under their own retention and service policies: Google Gemini API terms, Deepgram privacy policy and ElevenLabs privacy policy.

Your rights

If you're in the UK, EEA, or a jurisdiction with equivalent law (e.g. California), you have the right to request a copy of the data we hold about your install, or have it deleted. Email privacy@subline.so with your account ID (Settings → Account in the app) and we'll action the request within 30 days.

Children

Subline is not directed at children under 13. We do not knowingly collect data from children under 13. If you believe a child has provided us data, email privacy@subline.so.

Changes

We may update this policy from time to time. Material changes will be posted here with the updated date at the top of the page.

Contact

Subline is operated by Float Labs Ltd. Questions about this policy: privacy@subline.so.