Account & security
Is email verification really compulsory?
Yes. Unverified accounts cannot sign in. Verification links expire in 24 hours and can be resent from the sign-in page.
How does two-factor work?
After your password, we email a six-digit code that expires in ten minutes. You can trust a device for 30 days. Ten single-use backup codes are available in Settings if you lose access to your inbox.
Can I sign in with Google?
Google OAuth can be enabled by the administrator. Email and password always works, and 2FA still applies.
What happens if I abort games repeatedly?
Five aborts in fifteen minutes triggers a one-hour ban from starting new games. Aborted games do not count toward daily achievements.
Credits & pricing
How much does analysis cost?
200 million nodes per credit. The default position search is 10 million nodes (0.05 credits). “Analyse deeper” adds another 10 million. Infinite mode is billed on actual nodes when you stop it.
Do credits expire?
No. Free and paid credits remain until used. Purchased credits are refundable within 14 days if unused.
How do I earn free credits?
Five on email verification, one per daily check-in, one per two completed games (up to 100 games/day), 0.5 per rewarded ad (admin-configurable), and achievements worth up to 25.
Why do displayed credits show two decimals but the ledger has nine?
We store and bill at nine-decimal precision so tiny analyses are not rounded away. The interface shows two decimals for readability; the full amount is always in your credit log.
Analysis & games
Which Stockfish version do you run?
Stockfish 19, compiled for the server architecture. The default depth and node budget are admin-configurable.
Can I analyse a whole game?
Yes. Batch analysis runs a full-game review at a configurable depth. A typical 40-position review at 10 MN is about two credits.
Are puzzle analyses cached?
Yes, to disk. Re-opening a cached puzzle reuses the stored analysis and charges the original node count once, never twice.
What time controls are available?
Bullet, blitz, rapid and classical presets plus custom controls up to one hour, with optional increment. Bots are available from depth 1 to 15 and are charged per game.
Puzzles & learning
Where do the puzzles come from?
15,000 of the hardest CC0 puzzles from the Lichess puzzle database, imported with their ratings and themes. We do not create fake users, games or payments.
What are generated puzzles?
When you analyse a game, blunders can become puzzles. For your own games they are “Fix mistake”; for other players they are “Find tactics”. Tough positions are labelled as such.
Data & privacy
Do you sell data?
No. We do not sell personal data or game history. Third-party scripts are limited to what payments, human verification and optional analytics require.
Can I export my games?
Yes. Every game exports as PGN, and your library can be exported as a single PGN archive. Import supports PGN and common variants.
How do I delete my account?
Email admin@chessurge.org from the account address. We remove personal data and retain only what accounting or abuse-prevention law requires.