Data storage and encryption

Overview

By default, all your data is stored locally on your device. Your text, stress analysis, and emotional insights are kept on your phone, tablet, or computer—never on our servers.

Local storage

CalmSignal stores all data locally on your device:

• Text analysis results: Stored in secure local storage (iOS: App Group, Android: Encrypted SharedPreferences)
• Settings and preferences: Stored locally in app storage
• Model data: AI models are stored locally (CoreML on iOS, ONNX on Android, ONNX in browsers)
• No cloud storage: By default, nothing is stored on our servers

Optional cloud sync (opt-in only)

If you choose to enable cloud sync (disabled by default), only aggregated insights are synced—never your raw text. When enabled, we encrypt data end-to-end using AES-256 with keys derived from your password. Our servers never store plaintext emotional transcripts—only aggregated insights and anonymized statistics.

Encryption

All data stored locally on your device is protected by your device's built-in encryption (iOS: Data Protection, Android: File-Based Encryption). If you enable optional cloud sync, data is encrypted in transit (TLS 1.3) and at rest (AES-256).