Esmero — Privacy Policy
Last updated: November 14, 2026
This policy explains what data Esmero ("the app") handles. It is published by Yabin Alejandro Lagunes Cuevas, trading as The Alchemist Code ("we"), who is responsible for the data. Contact: [email protected].
The short version
- Local mode needs no account. Clients, appointments, history, services, photos, inventory, cash records and settings stay on your phone.
- Esmero Business is optional. Turning on the booking link creates an account with your email and password, and stores part of your business and agenda in Firebase (Google). Clients book and cancel as guests without installing an app or creating an account.
- Appointment reminders are scheduled on your phone. If you enable new-booking alerts, Firebase Cloud Messaging does send a push notification to the business phone.
- The app does not use your location or contact list. You choose photos individually or use the system camera. Visit photos are never uploaded to our servers.
- The app shows ads and uses analytics and crash reporting; those services collect the technical data described below.
Data stored on your phone
Your business profile, clients (name, optional phone and notes), services, appointments, visit history, optional photos, products, stock movements, sales, daily cash records and settings are stored locally.
- Visit photos (Premium): saved in the app's private folder and never uploaded.
- Backup and CSV: created only when you ask. You decide where to save or share them; we never receive them.
- Android backup: if enabled in your Google account, Android may include app data in the device backup. Android encrypts and stores it in your account; we cannot access it.
Inventory and cash are always local, including when Esmero Business is on: they are not synced to the cloud or between phones. Use Settings › Delete all my data to erase the local copy. Uninstalling the app also removes it from the phone.
Esmero Business (optional): account, cloud and booking link
If you turn on Settings › Booking link, in addition to local storage:
- Business account: Firebase Authentication stores your email and encrypted password. We never see your password.
- Connected data: your business name, services, hours and appointments uploaded by the app are stored in Cloud Firestore. When a client books through your link, their name, optional phone, chosen service and time are also stored. Visit photos are not uploaded.
- Sync scope: web bookings arrive on the connected phone. This is not a full multi-device backup: clients, products, stock, sales and cash are not restored from the cloud, and a local appointment not yet uploaded does not appear on another phone.
- Guest management: the appointment stores a hash of the management token. So a retry with the same request identifier cannot duplicate a booking, the idempotency record keeps the response containing the token; that record is only accessible from the server. The link carries the token in its fragment, which is not sent in the page's HTTP request.
- Public page: it carries no ads or first-party analytics. Firebase Hosting logs the IP and technical data needed to serve and protect it. To limit spam, Functions derives a truncated, pseudonymous daily identifier from the IP and business (the raw IP is not stored) and keeps it in Firestore with the booking counter until account deletion.
- Push notifications: if allowed, the device push token is stored with the business to alert you about new bookings. It is removed when invalid or when you delete the account.
- Disconnect: prevents new public bookings and stops sync on that phone, but does not delete the business or cloud appointments. Someone with an existing appointment can still open their link to view or cancel it.
- Account deletion: "Delete my account and cloud data" removes the account, business, link, bookings and connected data. The local copy remains until you delete it separately.
Connected data is kept until you delete the account or ask us to help remove it. We never use it for advertising or sell it.
Your clients' data is yours to look after
You decide what information about other people to record and for how long. Where required, tell clients what you keep and why, ask permission before taking a photo, and delete their record when requested. In connected mode, their data passes through Firebase (us-central1) to provide the agenda and booking service. If a client asks you to erase their data, cancel the appointment and write to us to remove their connected data.
Data collected by third-party services
| Service | What it collects | Why |
|---|---|---|
| Google AdMob | IP, advertising and app-set identifiers, interactions and diagnostics | Ads, measurement and fraud prevention |
| Google Analytics for Firebase | Instance ID, advertising identifiers, approximate location, screens, sessions and purchase events | Understanding app usage |
| Firebase Crashlytics | Crash traces, device, app state and installation identifier | Finding and fixing crashes |
| Firebase Remote Config | Country, language, time zone, OS and version | Remote configuration |
| Google Play Billing / App Store | Purchase and payment data | Processing Premium; we never see your card |
| Firebase Authentication (Esmero Business only) | Email and encrypted password | Business account |
| Cloud Firestore and Functions (Esmero Business only) | Business, services, hours, appointments, bookings and the daily pseudonymous IP-derived identifier | Link, connected agenda, spam prevention and deletion |
| Firebase Hosting (Esmero Business only) | Visitor IP and technical data | Serving and protecting the public page |
| Firebase Cloud Messaging (Esmero Business only) | Device push token | New-booking alerts |
On iOS, these services may use device identifiers and Analytics may collect IDFV. IDFA is available only with tracking permission. AdMob, Analytics, Crashlytics and Remote Config do not receive the content of clients, appointments, photos, inventory or cash; Firebase does process the connected data described above. Everything is encrypted in transit.
- Google: https://policies.google.com/privacy
- Apple: https://www.apple.com/legal/privacy/
- How Google services use data: https://policies.google.com/technologies/partner-sites
Your choices
- Personalized ads (EEA, UK and Switzerland): choose before they appear and change your choice in Settings › Ad privacy options.
- Advertising identifiers: reset them or deny tracking in system settings. Denying IDFA does not prevent the other technical identifiers described above.
- Notifications: reminders and booking alerts are optional; revoke permission in system settings. Android also offers optional subscription-renewal reminders.
- Premium removes all ads.
Your rights
Request access or deletion at [email protected]. In local mode, Settings › Delete all my data erases the phone's information. With Esmero Business, also use Delete my account and cloud data. Deleting data does not cancel a subscription; manage it in Google Play or the App Store.
Children
The app is not directed at children under 13 and we do not knowingly collect their data.
Changes
The current version will be posted at this address with an updated date.
Contact
Yabin Alejandro Lagunes Cuevas (The Alchemist Code), Mexico · [email protected]