Short, because there is not much of it. Last changed 9 September 2026.
The short version. Your cards live on your phone. If you never sign in, nothing about your collection ever leaves it. We count anonymous events so we can tell whether the app works. We do not sell anything about you, because we do not have anything worth selling.
Every swipe, want, owned card, your handle, your budget and what the app has learned about your taste are stored in your browser, on your device. Clearing your browser data deletes them. Use export my binder in the Me tab to keep a copy.
Signing in is optional and the app works fully without it. If you sign in with Google we receive your Google account's email address and a user id, and we store them with a copy of your binder so it can follow you to another phone. That is the whole reason the sign-in exists.
Your binder and your email are held in a database run by Supabase, in the United States. We do not post anything to your Google account and we cannot read anything else in it.
The app records anonymous events, like a card being swiped, a search being run, or a want list being opened. They carry no name, no email and no card list, and are tied to a random id for that device. We look at them in aggregate, to answer questions like whether people come back and whether search finds anything. Vercel, who host the site, also keep basic anonymous traffic counts.
Prices come from public card catalogues and are a guide, not a quote. They can be stale or wrong. When you tap a buy button we send you to TCGplayer or eBay with the card in the link, and nothing else. We earn a commission on what you buy through the eBay link. It costs you nothing extra and it does not change what the app shows you or how the list is ranked.
Grail Guide is not built for children and we do not knowingly collect anything from anyone under 13. If you are a parent and think we have, write to us and it goes.
Grail Guide is in beta and being built in the open, so this page will change as the app does. The date at the top is the last time it did.
Card images and names are © Nintendo, Creatures, GAME FREAK and The Pokémon Company. Grail Guide is a fan project and is not affiliated with them, or with TCGplayer. Catalogue data comes from pokemontcg.io and TCGdex.
Ask us anything: daniel@mithrilslabs.com. A real person reads it.