Privacy Policy

SmileStreak photographs your smile, so it handles face data. This section describes every part of that handling — what is collected, how it is used, where it is stored, how long it is kept, and how you delete it.

• What face data is collected.Two things, both on your device only. (1) Selfie photographs of your face, captured by the front camera when you take a smile scan. (2) Transient face landmarks — while the scan screen is open, Apple's on-device Vision framework locates a face bounding box and the lip contour in each camera frame so the app can find the region of your teeth to measure. SmileStreak does not create, derive, or store a faceprint, face template, face geometry map, depth map, or any other biometric identifier, and it does not use Face ID, the TrueDepth camera, or ARKit face tracking.
• How it is used.The lip landmarks are used only to crop the mouth region of the current frame so brightness, evenness, and stain contrast can be measured, producing your 0–100 Smile Score. The landmarks exist in memory for the duration of a single frame and are then discarded — they are never written to storage. The selfie itself is saved so you can see your scan history and your before & after comparison. Face data is never used to identify, authenticate, or recognize you, never used for advertising or profiling, and never used to train any model.
• Where it is stored.Selfies are written to SmileStreak's private app container on your iPhone. Smile Scores and their component measurements are stored beside them in a local SwiftData database. Nothing is stored on a server — SmileStreak has no backend and Stack Curious operates no servers that receive face data. If you have iPhone backups turned on, this app data is included in your own Apple device or iCloud backup, which is controlled and encrypted by Apple under your Apple Account; we have no access to it.
• Sharing with third parties.Face data is never shared with any third party. It is never transmitted off your device by SmileStreak — not to us, not to any analytics, advertising, cloud, or AI service, and not to any other company. The one exception is entirely under your control: if you tap the share button on a before & after card, iOS hands that image to the destination you personally choose in the system share sheet.
• How long it is retained. Transient face landmarks are discarded within the same frame — retention is effectively zero. Selfies and Smile Scores are retained on your device for as long as you keep them: there is no server-side copy and therefore no server-side retention period. We cannot retain what we never receive.
• How it is deleted. Open Settings → Your data → Delete all my data inside the app. This permanently erases every stored selfie, thumbnail, Smile Score, streak, and preference from the device. Deleting the SmileStreak app removes all of it as well. Because no copy exists anywhere else, deletion on your device is complete deletion.

• We do not use analytics SDKs of any kind.
• We do not track you across apps or websites.
• We do not require an account, email address, or login.
• We do not upload your photos or send them to any server.
• We do not sell, share, or transmit any personal data to third parties.
• We do not display advertising.
• We do not use the Apple Advertising Identifier (IDFA).
• We do not operate any servers that see your face, your scores, or your activity.

• Smile photos.The selfies you capture are saved to SmileStreak's private storage area on your device. They are never uploaded and are only used to display your history and generate before & after comparisons on-screen.
• Smile Scores & scan history. Each scan's 0–100 score and its component measurements (brightness, evenness, whiteness) are stored locally with Apple's SwiftData framework. Local-only.
• Program & streak progress. Your 30-day plan, completed daily tasks, and current streak are stored on your device. Local-only.
• Goal & onboarding choices. The goal you pick (for example, whiter smile or event prep) and related preferences are stored on your device and used to personalize your plan. Local-only.
• Notification preferences. Your reminder settings are stored on your device. Local-only.
• Purchase entitlement.Whether you have bought the Full Glow-Up Unlock is verified through Apple's StoreKit framework on your device. We never see your payment details.

SmileStreak uses your front camera only while the scan view is open. After your first (baseline) scan, the app locks exposure and white balance so later photos are measured under consistent lighting. Frames are processed in real time by Apple's on-device Vision and Core Image frameworks to detect your smile and compute a score. We do not stream, record, or transmit any camera data.

SmileStreak only writes to your Photos library if you explicitly choose to save or share a before & after card. Share cards are rendered in memory on your device and leave the app only through the standard iOS share sheet, at your direction, to the destination you pick.

SmileStreak has no backend. The app makes no calls to any SmileStreak server, because none exists. The only network interaction is with Apple's own systems — StoreKit for verifying your purchase and the local notification system for reminders. Your photos and scores are never part of any network request.

If you grant notification permission, SmileStreak schedules local reminders to keep your streak alive. These are generated and delivered entirely on your device — no data passes through any third-party push service.

The Full Glow-Up Unlock is a one-time, non-consumable in-app purchase processed by Apple through the App Store. We never see your payment details. Refunds are handled by Apple in accordance with their policy.

SmileStreak is not directed at children under 13 and does not knowingly collect information from anyone under 13.

If this policy materially changes, we will update the “Last updated” date above. Since the app collects nothing and has no servers, material changes are unlikely.

Questions: hello@stackcurious.com