Spiral Journey

Privacy Policy

Last updated: March 2026

Overview

Spiral Journey ("the app") is a circadian rhythm tracker for iOS and Apple Watch. This policy explains what data the app accesses, how it is used, and your rights.

Data We Access

Apple Health / HealthKit

With your explicit permission, the app reads the following data from Apple Health:

Sleep analysis — sleep stages (deep, REM, core, awake) to calculate circadian rhythm metrics, detect patterns, and provide recommendations.
Heart rate & HRV — resting heart rate, heart rate variability (SDNN), and high heart rate events to track autonomic health and detect anomalies.
Activity — step count, exercise minutes, active calories, and workouts to compute your circadian activity rhythm (cosinor analysis) and auto-populate exercise events on the spiral.
Temperature — wrist temperature deviation as a proxy for circadian phase.
Daylight exposure — time in daylight to correlate with sleep quality.
Menstrual cycle — flow data to detect ~28-day cycles in sleep patterns.
Caffeine — dietary caffeine intake (if logged by a compatible app) to auto-populate caffeine events.

The app does not write any data to Apple Health.

Calendar (optional)

If you grant permission, the app can read your calendar events to create context blocks (work, study, commute) and detect conflicts between your sleep schedule and daily obligations. Calendar data is processed entirely on your device and is never transmitted to any server.

Microphone & Speech Recognition (optional)

If you grant permission, the app uses on-device speech recognition (Apple's SFSpeechRecognizer) to transcribe your dream journal entries by voice. Audio is processed entirely on your device using on-device recognition — it is never sent to external servers or stored after transcription.

Local Network / Peer Comparison (optional)

The app can discover nearby devices running Spiral Journey via Multipeer Connectivity (Bluetooth/WiFi) for anonymous sleep profile comparison. Only aggregated metrics (consistency score, mean duration, chronotype, etc.) are shared — no raw sleep records, health data, or personal information. The connection is encrypted by default. Data from the other device is ephemeral and is deleted from memory when the session ends. No peer data is stored permanently.

Notifications (optional)

If you enable notifications, the app sends local reminders for sleep goals, morning summaries, and predictive alerts. No notification data is shared externally.

Data We Do NOT Collect

No personal identifiers (name, email, phone, location)
No advertising identifiers or tracking
No analytics services or third-party SDKs
No advertising or analytics data is transmitted to third-party tracking servers
No data is sold, rented, or shared with any third party

On-Device Processing

All analysis — including the SleepDNA Engine, NeuroSpiral 4D (Clifford torus geometry, tesseract micro-states, winding number analysis), Lomb-Scargle periodogram, Poisson/Hawkes event modeling, codon analysis, pattern detection, health markers, Hilbert phase analysis, persistent homology, and ML predictions — is performed entirely on your device. No sleep or health data is sent to external servers.

Data Storage

Primary app data (sleep episodes, circadian events, predictions, coach messages, goals, and training metrics) is stored locally on your device using SwiftData. If iCloud is enabled on your Apple account, records may be synced using Apple's CloudKit private database so your own devices stay in sync. This data is only accessible to your Apple ID — Apple does not have access to your CloudKit private database content.

Home Screen Widget

The Spiral Journey widget displays sleep summary data on your home screen. It reads data from a shared App Group container on your device. No data leaves your device through the widget.

Background Processing

The app performs two daily background tasks:

Model retraining — updates the on-device ML prediction model using your local sleep history (requires device to be charging).
SleepDNA refresh — recomputes your sleep pattern profile.

Both tasks run entirely on-device; no data is transmitted over the network.

On-Device AI Models

If you enable the AI coach chat feature, the app may use one of two on-device model options:

Phi-3.5 GGUF — an open model file downloaded from Hugging Face to your device. After the initial download, all prompts and responses are processed locally. The model is automatically unloaded from memory when you leave the chat.
Apple Foundation Models — on iOS 26 and later, the coach can use Apple's built-in on-device Foundation Models. No network connection is required and no data is transmitted.

In both cases, your conversations and sleep data remain on your device. Chat history is stored locally and is not synced to iCloud.

Apple Watch

Data synced between your iPhone and Apple Watch uses Apple's WatchConnectivity framework. This communication is direct device-to-device and is never routed through external servers. The Watch app reads sleep data from HealthKit independently and shares it with the iPhone app via a secure App Group container.

Data Retention

The app enforces automatic data retention policies to keep storage manageable. Older prediction history and training metrics are periodically trimmed. You can manually delete all your data at any time from the Settings tab ("Reset All Data").

Children

The app is not directed at children under 13 and does not knowingly collect data from children.

Changes to This Policy

If this policy changes, the updated version will be published at this URL with a new "Last updated" date.

Not Medical Advice

Spiral Journey is an educational tool for self-observation of sleep patterns. It does not provide medical diagnoses, clinical recommendations, or treatment plans. Always consult a healthcare professional for medical concerns about your sleep.

Contact

If you have questions about this privacy policy, contact us at xaron98@gmail.com or open an issue at github.com/xaron98/spiral-journey.