Deck Compare does not collect, sell or transmit any personal data. There is no account, no sign-in, no analytics, no tracking and no telemetry.

What the extension reads: the decklist (card names and quantities) of the public deck pages the user chooses to compare, on the supported deck sites, or text the user pastes.

What it stores, locally only (storage.local, never synced or sent anywhere): the user's settings (the in-page button switch, the deck-site usernames they enter to list their own public decks, the results page's display density), the decks they add to a cross-comparison and its card filters, the comparison handed from the popup to the results page, and a cache of card data (types and image URLs) from Scryfall.

Network requests: only to the supported deck sites, to fetch a deck the user chose to compare, and to Scryfall (api.scryfall.com, cards.scryfall.io) for card types and images. Requests carry only public deck identifiers and card names.

Full policy: https://mcouzinet.github.io/deckCompare/privacy-policy.html