Privacy and product behavior
Privacy Policy
This policy describes how the current FastCue product stores records, uses diagnostic services, handles export and restore, and prepares support email.
Data controller and contact
The data controller for FastCue is Reverse Insight, a sole proprietorship in the Republic of Korea. The business address is Unit 602, Building 112, 127, Buil-ro 9-gil, Guro-gu, Seoul, Republic of Korea. Privacy contact: reverseinsight.official@gmail.com.
Core records on your device
Fasting, manual weight, tags, and related records are stored on your device in a Drift/SQLite database. Some settings, goals, and recovery snapshots use SharedPreferences, and Insights are calculated on the device with rules-based logic. The current production release works without signup and does not offer a public sign-in account. It does not upload local fasting, weight, tag, or settings records or transfer or restore them automatically after a device change or app reinstall. When available, Pro JSON export and import lets you move a backup file yourself.
Data handling on this website
The application code for this website sends no analytics events, sets no analytics cookies, writes nothing to localStorage, and accepts no user accounts or health records. Hosting and network providers may process ordinary request information needed for security and content delivery under their own policies.
Firebase diagnostics and optional product analytics
Firebase initializes before the app interface. In the current account-free iOS release, FastCue derives a pseudonymous per-install Support ID by applying a one-way hash to a Firebase Installations identifier. The raw Installations identifier is not shown in FastCue and is not sent to RevenueCat or support. Some current app versions with limited account functionality may instead use a pseudonymous Firebase Authentication account ID. Release builds use Crashlytics; the account-free iOS release clears its custom user identifier and does not set the Support ID or raw Installations identifier there. Firebase Analytics collection is off by default and starts only after you opt in. When enabled, it processes basic app-use information such as the app instance, device and operating system, app version, approximate location derived from an IP address, sessions, first opens, updates, and engagement. FastCue also records canonical screens and meaningful actions and results for navigation, fasting workflows, record management, Insights, notification permissions and settings, backup import and export, and subscription flows, together with the app language and Free or Pro status. Automatic screen-view collection remains disabled; FastCue manually records only approved canonical screen names. FastCue does not set the Support ID, raw Installations identifier, or pseudonymous Firebase Authentication account ID as a GA4 User-ID and does not send fasting times, weight or goal values, dates, tag names, record contents or counts, free text, or other health records to Analytics.
Subscriptions and RevenueCat
Production releases enable RevenueCat. RevenueCat processes purchase history, purchase and restore operations, entitlement status, a RevenueCat-provided country signal, and the pseudonymous per-install Support ID shown in FastCue. This required subscription processing runs even without Analytics consent. In the account-free iOS release, FastCue derives this Support ID through a one-way hash of a Firebase Installations identifier and sends only the derived ID—not the raw identifier—to RevenueCat as its custom App User ID. FastCue stores the first successfully derived Support ID in local app preferences before using it. A later Firebase Installations identifier rotation does not change the Support ID during that same app installation. If local app data is cleared or the app is deleted and reinstalled, the stored ID can be lost and a new Support ID can be created. FastCue uses it to check subscription access and help with support requests; it does not contain your email or name, and FastCue does not send fasting, weight, or tag contents to RevenueCat. Lifetime access manually assigned to a Support ID does not move automatically to a new ID, while store purchases follow that store’s restore process. RevenueCat uses the transaction country when available and otherwise the country derived from the last-seen IP address; it drops the IP address after deriving the country. The derived country can remain in the customer profile after the raw IP address is discarded. The approximate activity country reported by Analytics and RevenueCat’s country signal have different sources and meanings, and neither is treated as precise location. Only after you grant Analytics consent does FastCue send a custom paywall impression tied to the current offering to RevenueCat. Only when you grant Analytics consent may FastCue share the separate Firebase app instance ID with RevenueCat for GA4 subscription-lifecycle attribution; this is not the Support ID or raw Installations identifier and is removed from RevenueCat when you deny or withdraw consent. The app store processes payment information under its own policies.
Manual export, restore, and snapshots
The Pro manual export sends readable, unencrypted JSON through the system share sheet, and the destination you choose then handles that file. After validation, restore transactionally replaces the current local data. Automatic SQLite snapshots are created before database schema migrations, not after every record change.
Support email
A support email draft can automatically include the app version, device model, operating system, and, when available, the pseudonymous Support ID for troubleshooting. You review and send it through the mail provider you choose. The FastCue website does not run a support-form backend.
Security and retention
Local records can remain on the device until you delete them or replace them through restore. The current production release does not upload portable records or settings. Exported JSON follows the protection of the destination you select. Firebase Analytics, Crashlytics, and RevenueCat retain and process pseudonymous service data according to each service’s retention settings and policies; FastCue manages identifiable records through their consoles and supported tools. Support request emails and handling history may remain to answer and document the request or meet applicable legal obligations, under the mail provider’s settings and policies. When handling a deletion request, we explain any records that need to remain and why. We do not promise one automatic deletion deadline for every service. Store records follow the store’s own retention and deletion policies.
Local and service-data deletion
FastCue does not create a public sign-in account. You can edit or delete local records in the app. To request deletion of identifiable pseudonymous service data, email reverseinsight.official@gmail.com directly, even after uninstalling FastCue. You do not need to reinstall the app. Include a previously saved Support ID if you have one; if not, contact us first so we can check what data we can identify. If FastCue is installed, Send Feedback is another way to prepare a draft with the Support ID when available. Do not email fasting, weight, tag contents, a JSON export, or other health data. We check which service records belong to your request and explain the deletion scope. This can include the identifiable RevenueCat customer profile, pseudonymous ID, country, attributes, and purchase history held by RevenueCat. A Support ID alone cannot identify all past Firebase Analytics or Crashlytics records, and deleting a RevenueCat customer does not delete all Firebase data. Each provider’s retention and deletion policies apply. Service-data deletion does not cancel an Apple or Google subscription or remove local records or exported files; manage these separately in the store, app, or file destination.
Your choices
You can use FastCue without signup. In the current production release, local records and settings do not move to another device or return after reinstalling the app. The available record-transfer option is Pro manual JSON export and import when available; import replaces the current local data. Recovery snapshots created before database schema migrations remain local to the device. The pseudonymous per-install Support ID is for subscription and support handling, not record restore. It remains pinned during the same app installation even if Firebase Installations rotates its identifier, but local app-data clearing or deletion and reinstallation can remove the pin and create a new ID. At the first Analytics prompt, you can allow or deny collection. You can later change or withdraw that choice in More; denial turns collection off and resets Analytics data stored locally on the device. You can also edit or delete records, review a support draft before sending, and choose where to share a manual export.
Changes to product behavior
If data handling or connected services change, this page will be updated to describe the actual product behavior. Review the current version of this page alongside the version of the app you use.
Effective date and last reviewed
Effective date: September 2, 2026. Last updated: September 8, 2026 (clarified service-data deletion requests and processing scope). The website data-handling description was last reviewed on September 7, 2026.
Privacy questions
Email reverseinsight.official@gmail.com with questions about FastCue privacy or a service-data deletion request. Do not attach health details or a JSON export.