1. Overview and Core Philosophy
Denk ("we", "us", "our", or "the Application") is an expense-sharing and balance calculation utility developed and operated by independent developer Ömer Faruk Ay ("Developer"). This Privacy Policy transparently explains how Denk collects, uses, stores, and protects information when you use our mobile application and related web services.
Our guiding principle is strict data minimization: we collect only the bare minimum technical data necessary to calculate shared group balances accurately and securely.
2. Information We Process and Store
Denk stores data in Google Cloud Firestore using server-enforced security rules. The specific data categories processed are:
| Data Category | Specific Fields | Purpose & Processing |
|---|---|---|
| User Identifier (UID) | Random anonymous string or linked provider UID | Authenticates requests and attributes expense contributions without requiring your real identity. |
| Display Name | User-chosen nickname (e.g., "Alex", "Ömer") | Displayed to fellow group members so peers can identify who paid for or participated in an expense. Editable anytime. |
| Account Linking (Optional) | Google or Apple authentication token | Allows optional backup and recovery across devices. External passwords are never seen or stored by Denk. |
| Group Information | Title, description, default currency, invite code | Enables organizing shared expenses. Invite codes (e.g., DNK-XXXXXX) allow voluntary member joining. |
| Expense Records | Integer minor currency amounts, category, notes, payers, split allocations, date | Calculates exact balances. All monetary figures are stored as integers (e.g. cents) to prevent rounding inaccuracies. |
| Settlement Records | Payer UID, recipient UID, amount, completion timestamp | Immutable transaction records confirming debt settlement between two members. |
3. Authentication: Anonymous by Default & Optional Linking
When you first launch Denk, an account is created using Firebase Anonymous Authentication. This assigns your installation a unique, random User ID (UID) without requiring:
- No email address or telephone number.
- No passwords.
- No social media profile permissions.
Optional Account Linking: To safeguard your groups and balances against device loss or replacement, you may optionally link your account via Sign in with Apple or Google Sign-In from the Settings screen. When linked:
- Your existing anonymous UID is preserved—requiring zero data migrations.
- Firebase Authentication securely manages the authentication token.
- Denk never receives, processes, or stores your Google or Apple credentials.
4. What We Do NOT Collect
To ensure full compliance with Apple App Store Review Guidelines and Google Play Data Safety policies, we explicitly declare:
- No Advertising: Denk contains zero advertisements, zero advertising SDKs, and does not collect or transmit Apple IDFA or Google Advertising ID (GAID).
- No Third-Party Analytics / Trackers: We do not integrate third-party marketing or tracking SDKs (no Facebook Pixel, no cross-app behavioral tracking).
- No Contact Book Access: We never request access to your device contacts or phonebook. Group members join exclusively through voluntary invite codes.
- No Location Data: We never access fine or coarse GPS device location.
- No Camera or Microphone: Denk does not request camera or audio permissions.
5. Supported Currencies and Languages
Denk is built for international groups and travelers:
- Currencies: Turkish Lira (TRY ₺), US Dollar (USD $), Euro (EUR €), British Pound (GBP £), Japanese Yen (JPY ¥), Canadian Dollar (CAD), Australian Dollar (AUD), Swiss Franc (CHF), and other global currencies.
- Locales: Native localization in English (EN), Turkish (TR), Spanish (ES), French (FR), and Italian (IT).
6. Security and Infrastructure
Denk relies on enterprise-grade cloud security provided by Google Cloud Platform / Firebase:
- Encryption in Transit: All communications between the app and our database use TLS 1.3 encryption.
- Encryption at Rest: Cloud Firestore documents are encrypted at rest using AES-256 standards.
- App Check Protection: API traffic is attested using Firebase App Check (Apple DeviceCheck / App Attest on iOS and Google Play Integrity on Android) to protect against unauthorized bots and scrapers.
7. Account Deletion, Ownership Transfer & Anonymization
You have full sovereignty over your data and can delete your account at any time:
In-App Deletion (Immediate)
Go to Settings → Privacy & Data → Delete Account. When you confirm deletion:
- Sole-Owned Groups: If you are the creator and sole member of a group, the group, its expenses, settlements, and invite codes are permanently deleted.
- Multi-Member Groups & Ownership Transfer: If you own a group with other active members, you are guided to transfer ownership to another member before deletion.
- Anonymization of Financial History: In shared groups where you participated, your member profile is anonymized: your display name is replaced with
"Deleted User"and a departure timestamp is recorded. Financial amounts, split allocations, and settlement totals are strictly preserved so other group members' balances and ledgers remain mathematically correct. - User Profile Purge: Your user document (
users/{uid}), associated subcollections (user_groups,join_requests), and Firebase Authentication credential are permanently deleted immediately.
Web Deletion Request (External)
If you uninstalled Denk or no longer have access to your mobile device, you can submit an account deletion request via our public Web Account Deletion Portal or by emailing denk@omerfarukay.com. We process verified web deletion requests within 30 days pursuant to Google Play Data Safety policies and GDPR regulations.
8. Legal Disclaimer & Developer Protection
Denk is provided by the Developer on an "AS IS" and "AS AVAILABLE" basis without warranty of any kind. Denk is an informational ledger calculation utility and is not a financial, accounting, or tax advisory service. The Developer assumes no liability for disputes arising from erroneous user-entered figures or peer settlements.
9. User Rights (GDPR, CCPA & KVKK)
Depending on your jurisdiction, you have rights to access, rectify, delete, and restrict processing of your personal data.
10. Contact Information
For questions or privacy inquiries, please contact:
Developer: Ömer Faruk Ay
Official Contact Email: denk@omerfarukay.com
Application: Denk Shared Expenses