Privacy policy

Last updated: 11 November 2026

Yenlens is a browser extension that identifies Japanese Pokémon cards on Japanese marketplace listings and estimates what they cost to buy and import. This page explains what data it uses, why, and how to delete it.

Who runs Yenlens

Yenlens is run by Harrison King, an independent developer. Email harrison@yenlens.com. You can contact this address about anything on this page.

What the extension sends

Only when you open a listing on a supported site (Mercari, Buyee, ZenMarket, Yahoo Auctions, PayPay Flea Market, Rakuma), the extension sends our server:

• the listing's title, description, price and web address
• what the page says about shipping inside Japan, and whether it's an auction
• your cost settings: destination country, proxy, shipping method, Buyee plan, card currency margin and which currency to show prices in
• a random ID created when you install the extension

It doesn't send your name, email, account details, cookies or any other pages you visit. We don't use your data for advertising and never sell it.

What we keep

• Card corrections: when you pick a different card in the panel, we keep the listing title, the listing's ID, the card you picked and your random ID, so other people opening the same listing see the right card.
• "Something wrong?" reports: what you chose, any note you wrote, the listing title and ID, the card and total we showed, and your random ID.
• Listings we couldn't match: the marketplace and listing title, with no ID, so we can improve matching.
• How often each card is looked up, with no link to who looked it up.
• Technical logs: our hosting provider records each request (including the IP address it came from) and any errors. These logs are deleted automatically after 30 days.
• Extension problem reports: if the extension can't read a page or reach our server, it sends the site name, the kind of problem and the extension version, and nothing else.

Your settings are stored in your browser, synced by Chrome if you use Chrome sync. Until you choose a country, the extension reads your computer's time zone to pick a sensible starting one (for example, Europe/Paris starts you on France). This happens in your browser and the time zone isn't sent anywhere.

Why

To identify the card, estimate the cost to your door, remember corrections, fix mistakes, and keep the service running and protected from abuse (rate limits use the random ID). Under UK and EU data protection law, our basis is legitimate interests in providing the service you installed.

Who processes it

• Google Cloud (Belgium) runs our server and keeps the technical logs.
• Supabase (Ireland, on Amazon Web Services) stores the database.

Neither may use the data for their own purposes. Exchange rates come from the European Central Bank through Frankfurter; no data about you is sent to them. When you click a price link, you go to that site (eBay, PriceCharting, Mercari, SNKRDUNK), which has its own privacy policy.

Deleting your data

Open the extension's settings and click Delete my data. This deletes every correction and report linked to your random ID, and gives the extension a new one. Uninstalling the extension stops all sending. You can also email harrison@yenlens.com for a copy of your data, to correct it or to delete it, and you can complain to your data protection authority (in the UK, the ICO).

Children

Yenlens isn't aimed at children under 13 and we don't knowingly collect data about them.

Changes

We'll update this page and its date when anything changes, and mention significant changes in the extension.