LineZ Privacy Policy Effective Date: 4/7/2026
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I. Information We Collect
LineZ ("we," "our," or "us") collects data necessary to calculate accurate wait times, verify venue presence, and improve our service.
A. Core Location & Sensor Data
The following data is collected while you are within the proximity radius of a venue. Collection stops automatically when you leave the venue area.
1. Precise Geolocation (GPS): Latitude, longitude, horizontal accuracy, altitude, speed, and course. LineZ requests background ("Always On") location authorization to monitor venue geofences and detect when you
are near a bar. Location coordinates are only logged when you are within or near a venue area — we do not maintain a historical log of your location outside these zones. Background location is used solely to
detect geofence entry and exit and to classify your state while the app is running in the background.
2. Barometric Pressure: Altitude readings (hPa) via the device barometer.
3. Ambient Sound Level (SPL): Decibel level (dB) measured via the device microphone. The microphone is used for audio metering only — no audio is ever recorded, stored, or transmitted. Audio is captured to a
temporary file on your device solely for level measurement. This file is discarded when measurement stops and is never sent off your device. The microphone is automatically deactivated once you are classified as
INSIDE a venue.
4. Motion Activity: Walking, running, or stationary state, detected via the device motion co-processor.
5. Magnetometer: Magnetic field readings (X, Y, Z in µT) used to detect indoor environmental anomalies.
6. Device Acceleration: Gravity-removed user acceleration averaged over a rolling window.
B. User-Generated Content
Photos you capture and submit of a venue are uploaded to our servers and are permanently deleted when the venue closes for the day. We also collect venue reports you actively submit, including: venue name, GPS
coordinates at time of submission, report type (add or remove venue), and your account ID.
C. Account Information
Email address, user ID, and session tokens are collected and required for account creation, Purdue email verification, leaderboard participation, and points balance.
D. State Transition Logs
Every time your classification state changes (e.g., WALKING → IN_LINE → INSIDE), a record of that transition is written to our database. This record includes your user ID, the venue ID, and the timestamp of the
transition. When a transition occurs with high confidence, a sensor snapshot at that moment — including approximate location, ambient sound level, motion type, barometric pressure, and magnetometer readings — is
also stored to improve classifier accuracy. These logs are associated with your account ID and are retained for service improvement and model retraining. You may request deletion of your data at any time by
contacting us at the address in Section V.
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II. Data Retention & Deletion
A. Real-Time Sensor Data
Sensor readings sent to our backend for live activity classification are processed in memory and cached in Redis with a 24-hour expiry. Raw sensor streams are not written to a persistent database. To reduce
battery and data usage, GPS uploads are throttled to 60-second intervals when you are classified as INSIDE a venue, and are suppressed entirely when your detected speed exceeds approximately 15 mph.
B. State Transition & Sensor Snapshot Logs
State transition records and associated sensor snapshots are written to our Supabase database and retained for model training, performance monitoring, and debugging. There is no automatic expiry on these
records. You may request deletion of your data at any time by contacting us at the address in Section V.
C. Photos & Venue Reports
Submitted photos are permanently deleted when the associated venue closes for the day. Venue reports are stored only for the duration of admin review and are permanently deleted upon approval or rejection. No
record of the submission is retained afterward.
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III. How We Use Your Information
Activity Classification: We combine GPS accuracy, motion type, ambient sound level, barometric pressure, and magnetometer data to classify your state as WALKING, IN_LINE, or INSIDE a venue. This classification
is performed in real time by our backend model.
Venue Data Enrichment: When a venue report is approved by an administrator, we automatically query the Google Places API to retrieve the venue's official operating hours. This call is made server-side at the
time of approval — not at the time of your submission.
Push Notifications: We use Apple Push Notification Service (APNS) to deliver state-transition confirmations to your device (e.g., notifying you when you are classified as IN_LINE). These are functional
notifications required for the app to operate correctly.
Admin Notifications: When you submit a venue report, an automated notification email is sent via Resend to our admin address. This email includes your reporter ID, the venue name, GPS coordinates, and a map link
for verification purposes.
Service Improvement: State transition logs and sensor snapshots are used to monitor app performance, diagnose sensor issues, and retrain our classifier model to provide more accurate wait time estimates.
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IV. Third-Party Services
We use the following third-party services to operate LineZ:
┌────────────────────────────────────────┬─────────────────────────────────────────────────────────────────────────────────────┬──────────────────────────────────────────────────────────────────────────┐
│ Service │ Purpose │ Data Involved │
├────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────────────────┼──────────────────────────────────────────────────────────────────────────┤
│ Supabase │ User authentication, venue records, UGC photo storage, and state/sensor log storage │ Account credentials, venue data, state transition logs, sensor snapshots │
├────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────────────────┼──────────────────────────────────────────────────────────────────────────┤
│ Google Places API │ Automatic enrichment of approved venues with official operating hours │ Venue name and coordinates (server-side only, on approval) │
├────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────────────────┼──────────────────────────────────────────────────────────────────────────┤
│ Resend │ Delivery of admin notification emails upon venue report submission │ Reporter ID, venue name, coordinates │
├────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────────────────┼──────────────────────────────────────────────────────────────────────────┤
│ Apple Push Notification Service (APNS) │ Delivery of in-app state-transition push notifications │ Device push token, notification content │
└────────────────────────────────────────┴─────────────────────────────────────────────────────────────────────────────────────┴──────────────────────────────────────────────────────────────────────────┘
We do not sell your data to third parties or use it for advertising purposes.
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V. Contact Us
For questions about this privacy policy or to request deletion of your data, contact us at:
linezapplication@gmail.com