Privacy policy

Last updated 4 November 2026

Erstwhile (erstwhile.io) is a daily investing game. This page explains what information the game keeps, why, and what you can do about it. Questions: support@erstwhile.io.

Playing without an account

You can play without signing up. When you do:

• In your browser we keep a random player ID, your results and your stats. They stay on your device, and clearing your browser data deletes them.
• On our server we keep that random ID with your result for each daily puzzle, so you can be ranked against other players. It isn't linked to your name or email.
• To limit cheating, we store a one-way code made from your IP address, the day's puzzle and a secret key. We can't turn it back into your IP address, and it changes every day. It only tells us whether two games that day came from the same connection.
• We count simple events, such as how many games were started or finished each day. These counts contain nothing about who you are.

If you sign in with Google

Signing in is optional and lets your record sync across devices. Google shares your email address and an account ID with us; we don't receive your password, contacts or anything else. We store these with your game history (your results, stats and the choices you made in each game), plus a sign-in cookie that keeps you signed in.

If you become a supporter

Supporter subscriptions are sold through Link, part of Stripe, which takes the payment and handles tax, receipts and billing questions. You give your payment details to Stripe and Link, not to us; their privacy policies apply to them (Stripe, Link). We never see or store your card details. We store, with your account, the Stripe customer and subscription IDs, which plan you're on, whether it's active and when it renews or ends, so the game knows you're a supporter. If your weekly streak save covers a missed day, we also store that date with your player ID.

No ads

Erstwhile doesn't show ads and doesn't use advertising or tracking cookies. No advertiser receives any information about you. The game is paid for by its supporters.

Cookies

The only cookies are the ones needed for signing in: a session cookie while you're signed in, and a short-lived security cookie during sign-in.

Who processes the data

The game runs on Cloudflare, which hosts the site and its database. Google handles sign-in if you use it. Stripe and Link handle supporter payments. We don't sell your information.

The Erstwhile Market and fair play checks

• If you claim a ticker, we store it with your random player ID and the day you claimed it, plus any warnings, trading halts or bans. Its price is worked out from your daily results.
• To keep the scoreboard and the Market fair, we check results for signs of cheating. The check uses your player ID, your results, the time each result was submitted and the one-way connection code described above. It never sees your IP address, name or email.
• It looks for patterns such as a near-perfect result straight after another game from the same connection, or near-perfect results several days in a row. A flag is only a prompt for review: a person looks at every case, and nothing happens automatically.
• If we find cheating, we may warn you in the game, halt your ticker's trading for a few days, or remove you from the Erstwhile Market (see the Terms). Your daily results keep counting on the scoreboard.
• We do this because we have a legitimate interest in keeping the game fair. If you think we got it wrong, email support@erstwhile.io.

How long we keep it

• Account data, including your supporter status, is kept until you delete your account. Stripe keeps payment records for as long as the law requires.
• Anonymous daily results are kept to show past rankings in the archive.
• Tickers, and any warnings, halts or bans linked to them, are kept while the ticker exists, so the same player can't simply list again.

Your choices and rights

You can delete your account at any time from My profile → Delete account. That removes your email address, synced history and supporter record from our server straight away, and cancels any supporter subscription. You can also email us to ask for a copy of your data, to have it corrected or deleted, or with any concern. If you're unhappy with how we handle your data, you can complain to the data protection authority where you live.

Children

Erstwhile isn't aimed at children. Accounts are for people old enough to use a Google account on their own in their country.

Changes

If this policy changes, we'll update this page and the date at the top.