Privacy Policy - FrimaBridge

Last updated: March 29, 2026

FrimaBridge ("the Extension") is a browser extension that copies product listings between Mercari and Rakuma flea market platforms. This privacy policy explains what data is collected and how it is used.

Data Collection

Data Stored Locally

The following data is stored in your browser’s local storage (chrome.storage.local) and never leaves your device:

• Product listing data — Title, description, price, images, category, condition, and shipping information extracted from Mercari listing pages
• Pairing records — Mercari URL and Rakuma URL pairs for ghost listing detection
• Monthly copy count — Number of copy listings performed in the current month (for free tier limit)
• Remote config cache — Cached DOM selectors and mapping data from our configuration server (refreshed every 24 hours)
• License state — Whether a Pro license is active (boolean flag)
• License key — Your Polar license key (if activated)
• Activation ID — Your Polar activation identifier (if activated)

Image Transfer

When you transfer a listing from Mercari to Rakuma, the Extension downloads product images from Mercari’s CDN (static.mercdn.net) through the browser’s background service worker. Images are:

• Downloaded temporarily to transfer to Rakuma’s upload form
• Not stored permanently — images exist in memory only during the transfer process
• Not sent to any external server other than Rakuma’s listing form

Ghost Listing Detection (Pro Feature)

When Pro is activated, the Extension periodically opens listing pages in background tabs to check for sold items:

• Opens jp.mercari.com/mypage/listings and fril.jp/sell in inactive tabs every 15 minutes
• Reads the listed item IDs from the page DOM
• Compares with stored pairing records to detect sold items
• Closes the tabs immediately after reading
• No data is sent externally — all comparison happens locally

Remote Configuration

The Extension fetches DOM selectors and category mapping data from our Cloudflare Workers server (api.webextlab.joifup.com/frima-bridge):

• Only selector patterns and mapping tables are fetched (no user data is sent)
• Cached locally for 24 hours to minimize requests
• Falls back to built-in defaults if the server is unavailable

Anonymous Analytics (Google Analytics 4)

The Extension sends anonymous usage events via the GA4 Measurement Protocol:

• extension_installed — sent once on first install
• extension_updated — sent on extension update
• listing_copied — sent when a listing is copied (source and target platform only)
• ghost_listing_prevented — sent when a sold item is detected (platform name only)
• weekly_active — sent once per week to measure active usage

License Validation (Polar)

If you activate a Pro license, the Extension communicates with Polar’s API (api.polar.sh) to:

• Validate your license key
• Activate/deactivate your license
• Periodically re-validate the subscription status (every 24 hours)

Only your license key is sent. No browsing data or listing information is transmitted.

Data NOT Collected

The Extension does not collect:

• Your Mercari or Rakuma account credentials
• Your browsing history
• Your personal information (name, email, address)
• Transaction or payment details
• Data from websites other than Mercari and Rakuma listing pages

Data Retention

• All listing data and pairing records are stored in chrome.storage.local and persist until you uninstall the Extension or clear extension data
• No data is retained on any external server
• Analytics data is retained by Google Analytics per their standard retention policy

Third-Party Services

Changes to This Policy

We may update this privacy policy from time to time. Changes will be posted on this page with an updated “Last updated” date.

Contact

If you have questions about this privacy policy, please contact us at [email protected].