Marbles roll down a track that players build. You bet on which one wins. You can play the whole thing for free, nothing you win can be cashed out, and every race can be checked afterwards.
The currency
Every account starts with 5,000 coins, free. You also earn them by winning races and by building tracks other people like, and if you want more, you can buy them.
Coins go one way only. They can be bought, but never cashed out: they cannot be sold, sent to another player, or withdrawn, and nothing you win has any cash value. Winning a race gets you more coins to play with and nothing else.
Buying is optional and always will be. Everything on this page works the same whether you have ever paid or not: the odds do not change, and a bought coin is worth exactly what an earned one is.
One bit of shorthand: on the betting buttons, K means thousand. So 1K is 1,000 coins, 2.5K is 2,500 and 5K is 5,000.
Buying coins
Coins come in packs. The sizes and prices are shown before you pay, and the payment is taken by our payment provider rather than by us, so your card details never reach MarbleRun.
If a payment is refunded or charged back, the coins go with it. The full pack is taken off your balance even if you have already played it, so the balance can end up below zero. You keep the account and you keep your tracks; you cannot place a bet until the balance is positive again, which you get to either by buying again or by earning: a track people like pays 100 a time.
That is the only way a balance can go negative. You can never bet more than you hold, so ordinary play cannot put you in debt.
How a bet pays
Every bet is against the house, at fixed odds. Each marble has a multiplier, fixed when the room opens, and a winning bet pays stake × multiplier. A losing bet is lost.
It works the same whether you race alone or with others. What anyone else stakes never changes what your bet pays: a player betting on every marble with one coin cannot take a big bettor's stake, and a big bettor cannot shrink anyone else's win.
There is no house cut. The multipliers are fair odds, so betting on every marble in proportion to its chances returns your stake whoever wins.
Where the odds come from
They are measured, not estimated. Before a track can host a race, the server runs it 30 times with different starting seeds and records how often each marble wins. Every race run on the track since adds to that record, so the odds sharpen the more a track is raced.
multiplier = (races counted + marbles) ÷ (that marble's wins + 1)
The +1 means a marble that has never won is still priced, rather than offered at infinite odds. A record of zero wins is a measurement, not proof it cannot win.
The longest multiplier is 3× the number of marbles (×24 in an eight-marble race), so no single bet can put the house in an absurd position. The odds taken off a capped marble are given back to the others, so the board stays fair. In the rare case the house cannot cover a win, every stake in the room is refunded instead.
Why you can trust the result
The outcome of a race is decided entirely by the track and a random seed. Nothing else influences it: same track, same seed, same finish order, on any machine.
The risk that creates is a server choosing the seed after seeing the bets. So the seed is committed to before betting opens. When the room opens you are shown:
seed commitment = SHA-256(server secret | room id | seed)
The seed and the secret stay hidden while bets are taken. Once the race has settled, both are published. Anyone can then:
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Re-hash the secret, room id and seed, and confirm it matches the commitment published before betting, proving the seed was fixed in advance.
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Re-run the race from that seed and confirm the finish order is the one they were paid on.
Both values appear on the race screen after settlement. A claim of fairness that cannot be checked is only a claim, so the numbers needed to check it are handed to you.
Building a track
Place pins, walls and spawn points, set a finish line, and submit. The server then runs those 30 races and decides whether the track is fit to bet on. It can come back rejected, for reasons worth knowing before you build:
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Dominated. One marble wins too often. Everyone would spot it and bet on the same marble, which is not a bet. The limit scales with the field: with 8 marbles it is about 40%, and it is never above 85%.
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Unreliable. Some marble reaches the finish in fewer than a third of runs. A marble that usually gets stuck is not worth offering odds on.
·
Too slow. A race has 90 seconds to finish. Tracks that trap marbles or simply run long are rejected.
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Too few marbles. Two is the minimum, or there is nothing to bet against.
A validated track is frozen. Editing one creates a new version, which is validated again, so a track that has raced cannot be changed underneath the results it already produced.
Earning by building
Building is the other way to earn, and it rewards tracks people actually enjoy rather than tracks merely submitted.
Your first validated track
500
Each like from another player
100
A track reaching 5 likes
250
The milestones are the point. A flat rate per like would pay the same for ten tracks with one like each as for one track with ten, so it would not prefer the better track at all. With them, concentrating effort on something good pays roughly one and a half to two times as much as spreading it thin.
The first-track bonus is paid once per person, not once per track. You cannot like your own track.
Watching a race
Races are simulated on the server and replayed on your screen, so everyone watching sees the same run. The camera can show the whole track, or follow the marbles, keeping every one still racing in view.
