Usage Statistics - Privacy Policy¶

Version: 1.0 (Draft) Last Updated: 2025-11-20 Status: Draft for Review

Overview¶

This document defines the privacy policy for Printernizer's usage statistics feature. It outlines what data we collect, how we use it, and how we protect user privacy.

Core Privacy Principles¶

1. Opt-In by Default¶

Usage statistics collection is OFF by default
Users must explicitly enable it
Clear explanation provided before enabling
Easy opt-out at any time

2. Transparency¶

Full disclosure of collected data
Users can view their local statistics
Users can export their data as JSON
No hidden tracking

3. Data Minimization¶

Collect only what's necessary
Aggregate data where possible
No personally identifiable information (PII)
No tracking across devices

4. Local-First Architecture¶

All statistics stored locally first
Submission only if user opts in
Works fully offline
User retains full control

5. Right to Deletion¶

Users can delete all local statistics
Submitted data removed within 24 hours of opt-out request
No data remnants after deletion

What We Collect¶

System Information (Non-Personal)¶

{
  "installation_id": "550e8400-e29b-41d4-a716-446655440000",  // Random UUID
  "app_version": "2.7.0",
  "python_version": "3.11.0",
  "platform": "linux",
  "deployment_mode": "homeassistant",
  "country_code": "DE"  // Derived from timezone setting, not IP
}

Purpose: Understand technical environment and deployment patterns

Printer Fleet Information (Anonymous)¶

{
  "printer_count": 3,
  "printer_types": ["bambu_lab", "prusa"],
  "printer_type_counts": {
    "bambu_lab": 2,
    "prusa": 1
  }
}

Purpose: Understand hardware ecosystem and multi-printer setups

What we DON'T collect: - ❌ Printer serial numbers - ❌ Printer names or labels - ❌ Network addresses or hostnames - ❌ Printer credentials

Usage Patterns (Aggregated)¶

{
  "period": "2024-11-14T00:00:00Z",  // Week start, no precise timestamps
  "job_count": 23,
  "file_count": 18,
  "upload_count": 5,
  "uptime_hours": 168,
  "feature_usage": {
    "library_enabled": true,
    "timelapse_enabled": false,
    "auto_job_creation_enabled": true,
    "german_compliance_enabled": false
  }
}

Purpose: Understand usage intensity and feature adoption

What we DON'T collect: - ❌ File names or content - ❌ Print job details (model names, materials, etc.) - ❌ Exact timestamps (aggregated to day/week) - ❌ User interactions or click tracking

Error Information (Anonymous)¶

{
  "period": "2024-11-14T00:00:00Z",
  "error_summary": {
    "connection_timeout": 2,
    "file_download_failed": 1,
    "unknown_error": 0
  },
  "error_contexts": [
    {
      "error_type": "connection_timeout",
      "component": "printer_service",
      "count": 2
      // NO stack traces, NO file paths, NO personal info
    }
  ]
}

Purpose: Identify common issues to improve stability

What we DON'T collect: - ❌ Full stack traces - ❌ File paths or system information - ❌ User input or configuration values - ❌ Network details

What We DON'T Collect (Strict Rules)¶

Personal Information¶

❌ Names, email addresses, or contact information
❌ Home Assistant usernames or credentials
❌ API keys or access tokens
❌ IP addresses (except temporary for rate limiting, not stored)

Location Data¶

❌ GPS coordinates
❌ IP-based geolocation
✅ Only country code derived from timezone setting (user-configured)

Behavioral Tracking¶

❌ Click tracking or UI interactions
❌ Time spent in different screens
❌ Mouse movements or keyboard input
❌ Session recordings

File or Print Data¶

❌ File names or paths
❌ File contents or previews
❌ Model names or descriptions
❌ Print settings or slicing parameters
❌ Thumbnails or images

Network Information¶

❌ Printer IP addresses or hostnames
❌ Network topology
❌ MAC addresses
❌ WiFi SSIDs

Device Identifiers¶

❌ Printer serial numbers
❌ Raspberry Pi serial numbers
❌ Home Assistant installation IDs
✅ Only randomly generated installation_id (not tied to hardware)

How We Use Collected Data¶

Development Insights¶

Feature Prioritization: Focus on features users actually use
Platform Support: Prioritize deployment modes (Docker vs HA vs Pi)
Bug Fixes: Identify common error patterns
Performance Optimization: Focus on bottlenecks that affect most users

Examples of Insights¶

Good (Privacy-Friendly): - "60% of users run Printernizer as a Home Assistant add-on" - "Timelapse feature is enabled by only 15% of users" - "Connection timeouts occur most frequently on version 2.6.x" - "Users with 3+ printers use the library feature 90% of the time"

Bad (Would Violate Privacy): - "User John Doe printed model 'Secret_Project.3mf' 5 times" - "Installation abc123 is located at 192.168.1.100" - "User clicked 'Settings' button 47 times last week" - "Printer serial XYZ123 is running firmware 1.2.3"

We DO NOT sell or share data with third parties
We DO NOT use data for advertising
We DO NOT cross-reference with other datasets
Data is used internally for Printernizer development only

Data Storage & Security¶

Local Storage (User's Device)¶

Location: SQLite database in Printernizer's data directory
Encryption: Standard filesystem permissions (no special encryption needed)
Retention: Indefinite, until user deletes or opts out
Access: Only Printernizer application

Remote Storage (If Opted In)¶

Location: Your SQL server (Europe-based recommended for GDPR)
Encryption: HTTPS in transit, encrypted at rest
Retention: 2 years (configurable)
Access: Development team only, no third parties

Security Measures¶

✅ HTTPS-only submission
✅ Rate limiting (max 1 submission per hour per installation)
✅ Input validation and sanitization
✅ No sensitive data in logs
✅ Regular security audits

User Rights (GDPR/CCPA Compliance)¶

Right to Access¶

Local Statistics Viewer: See all collected data in the UI
Export to JSON: Download complete local statistics
Transparency: Full disclosure of submission payload

Right to Deletion¶

Delete Local Statistics: Remove all data from local database
Request Deletion: Submit opt-out request to delete remote data
Deletion Timeline: Within 24 hours for remote data

Right to Opt-Out¶

Easy Toggle: Single checkbox in settings
Immediate Effect: No more data submitted after opt-out
Historical Data: Existing data can be deleted separately

Right to Portability¶

Export Format: Standard JSON format
Complete Data: All local statistics included
Machine-Readable: Easy to process or transfer

Compliance¶

✅ Lawful Basis: Consent (opt-in)
✅ Data Minimization: Only necessary data collected
✅ Purpose Limitation: Used only for development insights
✅ Transparency: Clear privacy policy and disclosure
✅ User Rights: Access, deletion, portability, opt-out
✅ Storage Limitation: 2-year retention policy

CCPA (California Consumer Privacy Act)¶

✅ Right to Know: Users can see collected data
✅ Right to Delete: Deletion available on request
✅ Right to Opt-Out: Easy opt-out mechanism
✅ No Sale: Data is never sold or shared

Children's Privacy¶

Printernizer is not directed at children under 13
No special provisions needed (business/technical tool)

Anonymization Techniques¶

Installation ID¶

Method: UUIDv4 (random, not derived from hardware)
Rotation: Can be regenerated manually
Purpose: Distinguish installations without identifying users

Temporal Aggregation¶

Method: Round timestamps to day/week boundaries
Example: 2024-11-14T00:00:00Z (week start) instead of precise timestamp
Purpose: Prevent timing-based identification

Geographic Aggregation¶

Method: Country code from timezone, not IP geolocation
Example: "DE" instead of city or coordinates
Purpose: Regional trends without precise location

Error Sanitization¶

Method: Remove file paths, stack traces, user input
Example: "connection_timeout" instead of "Failed to connect to printer at 192.168.1.5"
Purpose: Useful error patterns without sensitive context

Changes to Privacy Policy¶

Notification¶

Users will be notified of material changes
Re-consent required for expanded data collection
Changelog maintained in this document

Version History¶

Version	Date	Changes
1.0	2025-11-20	Initial draft

Contact & Questions¶

For privacy questions or data deletion requests: - GitHub Issues: https://github.com/schmacka/printernizer/issues - Label: privacy

Response Time: - Privacy inquiries: Within 72 hours - Deletion requests: Within 24 hours

Sample Data Payload¶

This is an example of what gets submitted if you opt in:

{
  "schema_version": "1.0",
  "submission_timestamp": "2024-11-20T12:00:00Z",
  "installation": {
    "installation_id": "550e8400-e29b-41d4-a716-446655440000",
    "first_seen": "2024-11-01T00:00:00Z",
    "app_version": "2.7.0",
    "python_version": "3.11.0",
    "platform": "linux",
    "deployment_mode": "homeassistant",
    "country_code": "DE"
  },
  "period": {
    "start": "2024-11-14T00:00:00Z",
    "end": "2024-11-21T00:00:00Z",
    "duration_days": 7
  },
  "printer_fleet": {
    "printer_count": 3,
    "printer_types": ["bambu_lab", "prusa"],
    "printer_type_counts": {
      "bambu_lab": 2,
      "prusa": 1
    }
  },
  "usage_stats": {
    "job_count": 23,
    "file_count": 18,
    "upload_count": 5,
    "uptime_hours": 168,
    "feature_usage": {
      "library_enabled": true,
      "timelapse_enabled": false,
      "auto_job_creation_enabled": true,
      "german_compliance_enabled": false,
      "watch_folders_enabled": true
    }
  },
  "error_summary": {
    "connection_timeout": 2,
    "file_download_failed": 1
  }
}

Size: ~800 bytes Frequency: Once per week (if opted in) Anonymity: No PII, no file names, no network info

Note: This is a draft document for internal review. Final version will be presented to users in the settings UI and on the project website.