Heads or tails only settles anything if both people see the same coin. This one lives in a shared room: call your side, send the link, and the toss plays out live on every screen at once.
Toss a coinCreate a room and you hold one face of the coin; whoever joins with your link holds the other. When both of you are ready the coin is tossed once, and both screens show the same spin and the same landing within about a tenth of a second of each other.
Just want a quick answer for yourself? Pick singleplayer and flip straight away — same coin, no second player needed.
A physical coin is very slightly biased towards the side that started facing up, and a practised thumb can do worse than that. Here the face is read from the first hex digit of an HMAC-SHA256 digest: sixteen equally likely digits, eight for heads and eight for tails.
You do not have to take that on trust. Before the toss the room shows a hash of the server’s secret seed; each player’s browser adds a seed of its own; after the match the secret is revealed. Anyone can recompute the digest and confirm the coin landed the way the maths says it had to.
Who serves first, who kicks off, who picks the map, who pays for the pizza, which of two names goes first on the slide. Anything with exactly two outcomes and two people who would rather not argue about it.
If the two outcomes are not really “heads” and “tails”, a singleplayer flip lets you rename the sides — the result then shows your own labels instead.
Each player holds one side of the coin and both screens show who has which, so there is no arguing about the call after it has landed. Want the other face? Ask for a swap in the lobby — it goes through only if your opponent accepts.
Yes. It is a single toss decided by the server and pushed to every device, not a separate random flip on each screen.
Completely — no signup, no ads, no limits on how many rooms you open.
Ready? Flip a coin online with friends — free, no signup, no ads.