How it works: modes, twists and fair draws

A tournament, step by step

1
Announcement
Date, time, mode, twists and prize are published in advance, with a countdown on the site. For a prize tournament, the prize wallet is funded before check-in opens, so anyone can see the money is there.
2
Check-in
Check-in opens three hours before the announced time and closes at that time. The first round starts 30 seconds later. With a name, it takes one click: tournaments without a prize need no wallet, a few times a day. A prize tournament needs a complete account (profile and wallet). No check-in, no participation. You can cancel while check-in is open.
3
Rounds
A 3-second countdown, then 5 to 30 seconds (shown on each tournament) to pick heads or tails. You can change your mind until the end. The coin lands about 10 seconds later, and the next round starts a few seconds after the result.
4
The end
How it ends depends on the mode, but the game always goes on until there is a winner. Some tournaments have a prize, shown in advance and paid in USDC on Base after the usual checks.

5 modes, 5 twists

Every tournament has one mode, which decides how you win and what a wrong call costs, and can add twists, which change how the rounds are played. They are shown on every tournament card, and the waiting room gives the exact rules of that tournament.

5 modes

Sudden Death

One life each: one wrong call and you're out.

The last one standing wins. Fast and brutal.
If a round would knock everyone out, nobody is out and the round is replayed.

Extra Lives

Every player starts with the same number of lives: every wrong call costs one, and you're out when none are left.

The last one standing wins. Tournaments last longer and comebacks are possible.
If everyone is wrong, everyone loses a life. If that would knock everyone out, the round is replayed instead and nobody loses anything.

Points Race

A set number of rounds, 1 point per right call. The most points wins.

Every round counts, even if everyone is wrong.
The best score after the last round wins. Players tied for it play a Sudden Death final.

Hot Streak

The first player to be right the set number of times in a row wins.

Nobody is out during the race. A right call adds 1 to your streak, a wrong call sends it back to 0, and every round counts, even if everyone is wrong.
If several players reach the target in the same round, they play a Sudden Death final.
If nobody gets there within the maximum number of rounds, the longest streak of the race wins, after a final if it is tied.

Diamond Hands

Right calls in a row grow your hand. One wrong call loses it, unless you bank it first. The most banked wins.

Every right call in a row grows your hand: 10, 30, 75, 150, then double each time. One wrong call and what is in your hand is gone.
Hold Bank, like the shield, to keep what is in your hand safe for good. Bank is free: you still play the round, and your next right call starts a new hand at 10. You can't Bank with an empty hand, in the final, or in a round where your shield is up; with Shield, a wrong call keeps your hand as it was.
After the last round, what is left in your hand is banked for you. The most diamonds banked wins; players tied for it play a Sudden Death final, with no Bank.
Diamonds are just this tournament's score: everyone starts from 0.

5 twists

Heads Up

1 vs 1 duels: each round, you face one opponent, and the coin settles your duel.

The players still in are paired at random by a public formula. Your opponent's pick stays hidden until picks close.
Different sides: the coin decides who wins the flip. In Sudden Death, the player who lost the flip is out. In Extra Lives, they lose a life, and you keep flipping against each other until one of you has no life left.
Same side: a draw. Only your duel is flipped again, with 10 seconds to pick at most, so no round is ever void.
With an odd number of players, one player, picked by the pairing formula, goes through without playing.

Twin Toss

Two coins fall at the same time every round, from the same public draw, and you pick a side for each.

Each wrong coin costs a life: both right and you lose nothing, one wrong costs one life, both wrong cost two.
In Sudden Death you need both coins right, a 1 in 4 chance, so about 3 players in 4 go out every round: short and brutal.
A round is void only if both coins together would knock out every player still in.

Respawn

Out is not always the end: as a ghost, the right streak brings you back.

From the round after you are out, keep picking as a ghost, during the normal round and on the same coin.
Be right the set number of times in a row and you're back in the game for the next round, with 1 life (also in Extra Lives).
A wrong pick or a round without your pick sends your ghost streak back to 0.
You can come back as many times as you like until the last round shown. After that, out is out, and playing as a ghost is just for fun.

Shield

One or more shields for the whole tournament: raise one, and a wrong call costs you nothing in the game.

Pick a side, then hold the Shield button to raise one for the round (tap to lower it, until picks close), at most one per round.
If your call is wrong, you lose nothing: in Sudden Death you stay in, in Extra Lives you keep your lives, in a Hot Streak your streak stays where it was (and in its final, you stay in). It still counts as a wrong call in the stats.
A raised shield is used up even if you were right, so the whole game is choosing the moment.

No Auto-Pick

No side is ever picked for you: you can't let luck decide in your place.

A missing pick counts as a wrong call in Sudden Death and Extra Lives. In a Points Race it scores no point, and in a Hot Streak it sends your streak back to 0.
In a Heads Up duel, you lose the flip unless your opponent did not pick either (a draw). In Twin Toss, a coin you don't pick counts as wrong.
Outside duels and races, if nobody picks, the round is void and replayed; after 3 such rounds in a row, the tournament ends with no winner and any prize rolls over to a later tournament.

Good to know

No pay-to-win. There is nothing to buy: every player has exactly the same chance of winning.
Your pick does not change your odds. The coin is drawn independently of all picks: every player always has exactly one chance in two.
Away or disconnected? You are not eliminated for that. A side is picked for you at random, shown on your screen, and you stay in or go out like everyone else. Nobody can know that side before picks close: it depends on a secret of the round, published right after, so anyone can check it. The No Auto-Pick twist is the exception, and so are ghosts in a Respawn tournament.
If a round would knock everyone out, it is void and replayed, so a tournament ends with a winner (unless 3 rounds in a row are void because nobody picked, with the No Auto-Pick twist). Rarely, the players still in share the win instead: after 64 draws (64 rounds in Heads Up).
At least 2 players. A tournament with fewer than 2 checked-in players is cancelled.
If something breaks on our side, the round is cancelled and replayed with the same players. The criteria are objective and applied automatically: we cannot cancel a round because we dislike its result.
Only real rounds count. Void and cancelled rounds are replayed under the same number and never count in round numbers or rounds survived.
Eliminated? Keep watching: you can still pick a side for fun each round as a ghost. With the Respawn twist, your ghost picks can bring you back.

Provably fair: how the coin is drawn

We never pick the result. It comes from drand, a public randomness beacon run by the League of Entropy, a group of independent organisations including Cloudflare, Protocol Labs and several universities. Every 3 seconds, drand publishes a new random number, signed by its network, that nobody can predict or change.

When picks close, all picks are written into public files and we publish their fingerprint (a SHA-256 hash), along with how many players picked each side. From then on, no pick can be changed without the fingerprint changing.
The fingerprint is recorded on Base, a public blockchain, in a transaction from our proof wallet. The round is decided by the first drand number published at least 3 seconds after that block: when the picks were sealed, it did not exist yet.
A few seconds later, drand publishes that number.
The result is computed by a public formula: the first bit of SHA-256("tossking:v1:<tournament ID>:<round>:<drand random value>"). 0 is heads, 1 is tails. Twists add their own public data (duel pairs, the second coin, ghost picks, raised shields), sealed and checked the same way: each tournament's verification page gives their formulas.

So we cannot know the result when picks are sealed, and we cannot change the picks once the result is known. Every tournament has a verification page where your own browser redoes all of these calculations from public data. It also shows any player's picks, round by round: follow the "See picks" link next to a name.

drand, live

Networkdrand quicknet

Latest draw...

Value...

Check it at the sourceapi.drand.sh

Friends

Open a player's profile to send a friend request. Your friends, your requests and your notifications live on your page: tap your avatar at the top. Your list is just for you, and there is no messaging.

Training

No tournament running? Training is a free heads-or-tails you play alone, at your own pace, with our server's coin: call as many flips in a row as you can. Medals mark 3, 5, 10, 15, 20, 25 and 30 in a row, and the training leaderboard ranks the best streaks. Without an account you get 100 flips a day; with an account, 500 a day and your streaks on the leaderboard; once your account is complete (profile and wallet), 5,000 a day.

Leaderboards and fun facts

The leaderboard ranks players over all tournaments or mode by mode, for today, this week, this month or all time. Click a column title to sort the board by that column. The "?" next to a title explains what the column counts.

The Fun facts tab collects the most unlikely things that happened. Players named in a fact earn mentions: a daily fact counts as 1 mention, a weekly one 3, a monthly one 10. Mentions are not XP: they unlock four avatar rewards, at 1, 10, 40 and 150 mentions.

Avatar rewards and level

Your avatar is an icon, a color and a frame. Ten colors and twenty icons are free. Ninety more pieces are unlocked by playing: thirty colors, thirty frames and thirty icons, earned in tournaments of every mode and twist, at Rumble tables, in training and through fun fact mentions. Each one shows its condition on your profile and where you choose your avatar.

You never have to claim a reward: it is worked out from your results.

Every reward also earns XP: common +10, rare +30, epic +90, legendary +270. Your XP sets your level, from 0 to 126, shown next to your name.

Questions

Is it really free?

Yes. No purchase, no deposit, no transaction, ever. Prizes are funded by the organizer and, later, by sponsors.

Why do I need a wallet?

To receive the prize in USDC on Base. You only need one for prize tournaments, and to play more than a few tournaments a day. You prove the address is yours by signing a message in your wallet: it is free and sends no transaction. Step-by-step guide.

What is Base?

Base is a public blockchain compatible with Ethereum, with very low fees. We use it to pay prizes in USDC and to record the fingerprint of every round before its draw. Your wallet address is the same on Ethereum and on Base.

How often are there tournaments?

Every hour for now. The next ones and their countdowns are on the tournaments page.

Can I watch without an account?

Yes. Every tournament, every result, the leaderboard and every proof are public. An account is only needed to take part.

Can someone win by creating many accounts?

That is the only way to cheat, so it is what we fight, with dedicated technology and close monitoring against bots and multiple accounts: one person, one account, one wallet. Multiple accounts lead to disqualification of all of them, and winners are checked before any payment.

Where can I play?

Anywhere in the world, from 18 years old.

Can I message other players?

No. There is no messaging on TossKing. You can add friends from their profile, and block anyone.

Simple to play. Impossible to rig.