Short, in plain language, and true. Last updated September 2026.
What we store. Your account email, and a hashed password — never the password itself. Your display name and timezone. Your binder: every buy and sell you record, with its date, quantity, price and any note you add. Your watchlists. Your saved screens: each one's name and filter conditions, which cards it matches, and the nightly record of which cards entered or left it. The time you last opened the app. Whether you have turned on Backtest checks in Settings. A session record for each sign-in, kept until it expires or you sign out. Short-lived tokens while you verify an email address or reset a password. And a note of which one-time explanations you have dismissed, so we stop showing them.
What we don't do. We don't sell or share your data or run ads. Your binder is visible to you alone.
Analytics. We use Cloudflare Web Analytics to count page views and measure how fast pages load. It records which page you opened, the page that sent you there, your browser's user agent, and page-timing measurements. It sets no cookies, reads nothing from your browser's storage, and does not follow you to other sites.
Cookies & local storage. Signing in sets one cookie, and we keep a matching session record until it expires or you sign out. Local storage holds two things only — your theme, and whether the colorblind-safe palette is on.
Deletion. Delete your account from Profile & settings and everything above is removed from our database immediately. You cannot undo this. Copies already in our encrypted backups are not edited; they expire on their own — nightly copies after 14 days, monthly copies after 365 days. Public market data is unaffected. Export your binder as CSV first if you want to keep the transactions — watchlists cannot be exported.
Not financial advice. Cardstock describes what the market did, not what it will do. Signals, screens, and backtests are research tools; decisions and their outcomes are yours.
Data accuracy. We collect none of the market data ourselves. Every price, sale and population figure comes from pricecharting.com — see About our data — and sales records and census reports contain errors upstream of us. The service is provided as-is, without warranty of accuracy or availability.
Fair use. Your account is for you. Don't scrape at volume, resell our data, or probe other users' information. We may suspend accounts that do.
Intellectual property. Cardstock is a fan-made analytics project. It is not affiliated with, endorsed by, or sponsored by Nintendo, The Pokémon Company, Creatures Inc., or any grading company or marketplace. Pokémon names and card references are used for identification only; all trademarks belong to their owners.