Txter Privacy Policy
Effective Date: February 1, 2026 | Last Updated: April 16, 2026
Txter is designed with privacy as a core principle. We collect no personal data, require no accounts, and all messages are end-to-end encrypted. Your identity is a cryptographic key pair that never leaves your device.
1. Introduction
Txter (“the App”) is a decentralized mesh messaging application that enables device-to-device communication using Bluetooth Low Energy (BLE) and Wi-Fi without requiring internet connectivity. This Privacy Policy explains how Txter handles data on your device and across the mesh network.
The App operates without centralized servers — there is no “backend” that stores your data.
2. Data We Collect
2.1 Data We Do NOT Collect
- No names, email addresses, or phone numbers
- No location data (GPS, cell tower, or Wi-Fi-based)
- No contacts or address book data
- No browsing history or app usage analytics
- No advertising identifiers
- No personal data is sent to any server, cloud service, or third party (see Section 5.3 for anonymized network telemetry on gateway nodes)
2.2 Data Stored Locally on Your Device
| Data | Purpose | Storage |
|---|---|---|
| Cryptographic key pair (Ed25519) | Your mesh identity — used to sign and encrypt messages | Android Keystore (hardware-backed) |
| Display name | Shown to your contacts within the mesh | Encrypted SharedPreferences |
| Mesh node ID | A pseudonymous identifier derived from your public key | Encrypted SharedPreferences |
| Messages (sent and received) | Your conversation history | Local database (ObjectBox), on-device only |
| Known contacts (public keys) | Trusted contacts you've exchanged keys with | Local database, on-device only |
| Routing metadata | Temporary data about nearby mesh nodes for message routing | In-memory only; not persisted to disk |
2.3 Data Transmitted Over the Mesh
- Your messages: Encrypted end-to-end using your Ed25519 key pair before leaving your device. Only the intended recipient can decrypt them.
- Relayed messages: Your device may forward encrypted messages from other users to help messages reach their destination. You cannot read or access the contents of relayed messages.
- Routing announcements: Minimal, pseudonymous routing data (node IDs and link quality metrics) is shared with nearby nodes to build mesh routes. This data contains no personally identifiable information.
3. Permissions and Their Purpose
| Permission | Why It's Needed | When It's Used |
|---|---|---|
| Bluetooth Scan | Discover nearby mesh network participants | While the mesh service is active |
| Bluetooth Advertise | Make your device visible to the mesh | While the mesh service is active |
| Bluetooth Connect | Establish encrypted data channels with mesh neighbors | When communicating with nearby nodes |
| Location (Android 11 and below) | Android system requirement for Bluetooth scanning — Txter never reads your location | Only on older Android versions during BLE scanning |
| Notifications | Show a persistent notification while the mesh service runs | While the mesh is active |
| Nearby Wi-Fi Devices | Create a temporary local Wi-Fi hotspot for inviting a friend | Only when you tap “Start Sharing” |
| Foreground Service | Keep the mesh connection alive in the background | While the mesh is active (notification shown) |
4. Encryption and Security
- End-to-end encryption: All messages are encrypted using Ed25519 keys before transmission.
- Hardware-backed key storage: Your private key is stored in the Android Keystore, which uses hardware security modules when available.
- Signed identity exchange: When adding a new contact, a signed cryptographic handshake prevents man-in-the-middle attacks.
- No plaintext storage: Sensitive data is stored in Encrypted SharedPreferences backed by AES-256-GCM.
5. Network Diagnostics & Administration
5.1 Network Health Diagnostics
To maintain mesh network reliability, Txter collects local network diagnostics including:
- Node health metrics: Battery level, connection quality, and network mode — displayed only on your device.
- Truncated geohash: A 4-character geohash prefix (covers ~40 km area) used for routing optimization. Higher precision is only activated temporarily by authorized administrators during critical security events.
- Network topology data: Anonymized link quality metrics between mesh nodes. No personally identifiable information is included.
5.2 Admin Command Architecture
All admin commands are cryptographically signed and require:
- Valid digital signature verification
- Time-bounded execution windows
- Anti-replay sequence numbers
- Rate limiting (max 10 commands/hour per admin key)
- Dual-key authorization for high-risk operations
- Automatic reversion without confirmation
5.3 Telemetry Upload (Gateway Nodes Only)
If your device acts as a gateway node, it may upload anonymized cluster health data. This contains no personally identifiable information and is purged after 2 hours.
6. Third-Party Services
Txter does not use any third-party analytics, advertising, crash reporting, or cloud services. Third-party libraries used locally: Lazysodium (crypto), NanoHTTPD (local HTTP), ZXing (QR codes), ObjectBox (local DB).
7. Data Sharing
Txter does not share any data with third parties. The only data leaving your device is encrypted messages and minimal routing metadata.
8. Data Retention and Deletion
- Messages are stored locally until you delete them.
- Routing data is held in memory only.
- Relayed messages are forwarded immediately and not stored.
- Uninstalling Txter removes all data. No data is stored remotely.
9. Children's Privacy
Txter does not knowingly collect data from children under 13. Since the App collects no personal data at all, there is no age-specific processing.
10. Your Rights
- Access: All your data is on your device.
- Deletion: Delete messages in-app, or uninstall.
- Portability: Identity export is planned.
- Revocation: No consent to revoke — we never collected your data.
11. Changes to This Policy
Changes will be reflected in the “Last Updated” date and communicated through app updates.
12. Transparency
We are committed to transparency about our data practices. Since all data is stored locally and nothing is transmitted to our servers, our privacy commitments are self-evident through the app's behavior.
13. Contact
Questions about this Privacy Policy? Email us at privacy@txterapp.com