Privacy Policy

Privacy Policy

Useful Tools Collection takes user privacy very seriously.

1. Information Collection

Information We Collect

This tool automatically collects the following information through Google Analytics:

  • IP address (anonymized)
  • Browser type and version
  • Operating system information
  • Pages visited and time spent
  • Referral sources and search terms
  • Device information (desktop/mobile)

Information We Do NOT Collect

  • Personally identifiable information such as name, email, phone number
  • Contents of uploaded Excel files
  • Contents of merged data
  • Any sensitive information entered by users

2. File Processing

Complete Client-Side Processing

All file processing occurs only in your browser.

✅ File processing flow:
1. User selects files
2. Browser reads files
3. Browser processes merging
4. Browser generates download file

❌ NOT sent to server:
- Uploaded Excel files
- Merged result files
- Any part of file contents

Data Security

  • Uploaded files are not sent to the server
  • Processed data is temporarily stored only in browser memory
  • All data is deleted when you refresh or close the page
  • No data transmission outside the browser

3. External Services

Libraries Used

This tool uses the following open-source libraries:

  • SheetJS (xlsx.js): Excel file processing (Apache License 2.0)
  • Bulma CSS: UI framework (MIT License)
  • Font Awesome: Icons (Font Awesome Free License)

These libraries are loaded from CDN but do not transmit user data.

Google Analytics

This tool uses Google Analytics to collect website visit and usage statistics.

Collection Purpose:

  • Analyze website visitor count and pageviews
  • Understand user behavior patterns
  • Improve and optimize services
  • Identify popular features

Google Analytics Data Processing:

Opt-out Methods:

Google AdSense

This tool serves ads through Google AdSense.

Ad Serving:

  • Content-based targeted ads
  • Interest-based ads (using cookies)
  • Remarketing ads

AdSense Data Processing:

Managing Ad Personalization:

This tool does not directly create cookies, but Google Analytics and Google AdSense use cookies.

Google Analytics Cookies

  • _ga: Unique ID to distinguish users (expires: 2 years)
  • _gid: Unique ID to distinguish users (expires: 24 hours)
  • _gat: Throttle request rate (expires: 1 minute)

Google AdSense Cookies

  • Cookies for ad personalization
  • Ad impression and click tracking
  • Interest-based ad targeting

Users can delete or block cookies in browser settings at any time:

  • Chrome: Settings > Privacy and Security > Cookies and other site data
  • Firefox: Settings > Privacy and Security > Cookies and Site Data
  • Safari: Preferences > Privacy > Cookies and Website Data

Note: This tool works without cookies, but blocking cookies may prevent ads from displaying.

5. Data Storage

Browser Memory

Uploaded files and processing results are temporarily stored only in browser memory.

Local Storage

No use of local storage or session storage.

Data Deletion

  • Page refresh: All data deleted
  • Browser tab close: All data deleted
  • No separate deletion operation needed

6. Third-Party Sharing

Excel File Data

Uploaded Excel files and merged data are NEVER shared with third parties.

  • Not stored on server, so sharing is impossible
  • File contents never leave the browser

Analytics and Ad Data

Data collected by Google Analytics and Google AdSense is shared with Google:

  • Google Analytics: Website visit statistics
  • Google AdSense: Ad impression and click data

This data is processed according to Google’s Privacy Policy.

7. Children’s Privacy Protection

This tool does not directly collect personally identifiable information, but Google Analytics and AdSense collect data through cookies.

Parents can block cookies in their children’s browsers or enable Do Not Track settings.

8. Security Measures

HTTPS Usage

The website is served over HTTPS with encrypted communication.

Open Source

The tool’s source code is public for anyone to verify.

Regular Updates

Security libraries are regularly updated.

9. User Rights

Data Access

  • Excel file data: Exists only in user’s browser, directly accessible by user
  • Google Analytics data: View in My Activity with Google account

Data Deletion

  • Excel file data: Automatically deleted when page is refreshed or closed
  • Cookie data: Can be deleted in browser settings
  • Google data: Request deletion in Google Account Settings

Data Portability

Files are processed only on the user’s computer, so already owned by the user.

Tracking Opt-out

10. Policy Changes

Changes to this Privacy Policy will be announced on the website.

  • Last Updated: October 23, 2025
  • Effective Date: October 23, 2025
  • Major Changes: Added Google Analytics and Google AdSense usage

11. Contact

For inquiries about this Privacy Policy, please contact us via GitHub Issues.

Summary

Key Points

  • ✅ Excel files are NOT sent to server (complete client-side processing)
  • ✅ No collection of personally identifiable information (name, email, etc.)
  • ⚠️ Visit statistics collection via Google Analytics (IP anonymization)
  • ⚠️ Ad serving via Google AdSense (cookie usage)
  • ✅ Users can opt-out of tracking and block cookies anytime

Most Important: Uploaded Excel files and merge results are processed only in the user’s browser and are never sent to or stored on the server.

This tool prioritizes user privacy, and data collection through Google services is used only for service improvement and operational purposes.

홈으로