How Prophecy Works

What is Prophecy?

Prophecy is a prediction market for friend groups. Create markets about anything — will it rain tomorrow, who's winning game night, which startup raises first — then bet with play-money points (or track real dollars). The best forecasters climb the leaderboard.

How does betting work?

Anyone can create a market with a question and a set of outcomes (Yes/No or multiple choice). When you bet, you set two things:

Your probability estimate — what you think the odds are for each outcome
Your stake— how many points you're putting behind your prediction (minimum 10)

The market's implied probabilityis the stake-weighted average of everyone's predictions. Bigger bets move the market more.

How is scoring calculated?

Prophecy uses relative Brier scoring— you're rewarded for being more accurate than the market at the time you bet, not just for being right.

Implied Probability

p̄[k] = Σ(p_i[k] · s_i) / Σ(s_i)

The market's consensus — each bettor's prediction weighted by their stake.

Relative Brier Delta

δ_i = Σ_k [ (p̄_i[k] - o[k])² - (p_i[k] - o[k])² ]

Positive δ means your prediction was closer to the truth than the market average when you bet — you “beat the market.”

Payout

payout_i = (δ_i · s_i) / Σ_W(δ_j · s_j) · Pool

Winners (positive δ) split the entire pool, weighted by their delta and stake. If nobody beats the market, everyone gets their stake back.

Market lifecycle

OpenAnyone can place bets. The implied probability updates with each new bet.

Betting ClosedNo more bets. The market waits for its resolution deadline.

VotingBettors vote on the actual outcome. A majority decides the result.

ResolvedOutcome is locked in. Payouts are distributed based on relative Brier scores.

How does resolution work?

After the betting window closes and the resolution deadline passes, a voting period opens. Every bettor on the market can vote for the outcome they believe actually happened.

When a majority of voting bettors agree on an outcome, the market resolves and payouts are distributed automatically. If no clear outcome can be determined, the market may be voided and all stakes returned.

What are points?

Every new account starts with 1,000 points. Points are play money — use them to bet on markets and climb the leaderboard.

Markets can also be created in real money mode, which tracks stakes in dollars. No actual payments are processed — you settle up with friends afterwards.