BJ21 — provably fair blackjack (play money)

Connecting…

IDLE — No active deadline

⏱

Table timeouts (configured)

Ready— Commit— Reveal— Action— Reconnect—

Dealer

Play money — not real moneyBlackjack pays 3:2Verify via Audit JSON, Offline, or History /g/hash

Waiting for connection…

Fairness Center

Play money only. Server locks first · you add your seed · round ends · you verify independently

Round progress

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1Lock

2Bet

3Commit

4Reveal

5Play

6Verify

Connecting…

🔒 Server seed hash (pre-bet lock)

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This hash is locked before the round starts. The house cannot choose a server seed based on your client seed.

Client seals

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No active boxes

Table fingerprint: —

Hashes appear when a player presses Ready (round then starts once everyone is Ready). Compare with others — different fingerprint = server showed different commitments

⚠️ Cards are fixed for this round. The house can see them but cannot change them — your box depends only on your seed.

Verify this round

Waiting

🌐 Offline

Independent Verify runs in this browser — it does not trust the server. Missing a pre-round pin is UNPROVEN (amber), not a pass. Offline: copy Audit JSON → the offline verifier (a separate site) → paste. Finished rounds: History → public page /g/<hash>.

🔬 Technical details hashes · chain · timeline

Chain & server

Seed chain (pinned in your browser)

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Next server seed hash (pre-bet lock)

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Active server seed commitment

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Server seed (reveal)

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Dealer lane key (HMAC-SHA512)

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Your side

Your client seed (summary)

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Client commitments (shortened)

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Round audit

Nonce

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Dealt audit

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Cancelled round rate

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Timeouts (live + config)

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Round timeline (proof order)

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📜 Activity log

Rules

Play money only — chips have no cash value

Blackjack

Each box draws from its own 6-deck shoe (its provably-fair lane). There is no shared shoe, so nobody else’s play changes your cards.
Dealer stands on all 17s (S17).
Dealer checks for blackjack right after the deal. A dealer blackjack ends the round, and you only lose your original bet. Blackjack against blackjack is a push.
Blackjack pays 3:2. Other wins pay 1:1, ties push.
Double on any first two cards, including after a split. You cannot double split aces.
Split once on two cards of equal value (e.g. K + Q), so at most 2 hands per box. Split aces get one card each. A 21 after a split is not a blackjack and pays 1:1.
No insurance, no surrender, no even money.

Table

Bets are 10 – 10,000 chips, whole numbers only. One box per player. Log in to play; guests can watch.
Chips are play money. They cannot be bought, sold or cashed out. If your bankroll drops below 10, Refill tops it back up to 10,000.
The round starts when every seated box is Ready. Once the table is sealed, seats, bets and Ready are frozen until the deal.
If any committed box fails to reveal its seed, the whole round is cancelled and every bet is refunded. Dealing without that seed would hand someone a choice between two dealer hands, so the round never goes on without it.
Leaving after the deal does not stop the round: the cards are already fixed, your hand stands when its turn comes, and a win is still paid.

Clocks

Feedback

Found a bug, a round that fails verification, or have an idea? Email [email protected]. For a round, include its game hash from History.

Terms & privacy

Play money only, 18+. We store your username, email, a hash of your password and your balance, plus login IPs for 90 days to stop abuse. No ads, no tracking. Read the full Terms & Privacy.