Bracket Tournaments

Sybil-resistant, ESPN-style prediction tournaments for sports and esports.

Beyond continuous asset markets, Prediction Arena runs full-bracket tournaments for major sports and esports events. These are the bracket pools you grew up filling out — except every entry is on-chain, every payout is automatic, and there is no commissioner who can disappear with the pot.

How a tournament works

1. Bracket published

   A complete bracket — every team, every seed, every round — is published on-chain when the tournament opens.

2. Players commit their entire bracket upfront

   Every player picks their complete bracket — all rounds, all matchups, all the way to the final — and commits it as a single, sealed cryptographic anchor before the first game starts. You cannot change your bracket later. Neither can anyone else.

3. Round-by-round reveals

   After each round of real-world games settles, players progressively reveal that round of their bracket. Reveals are matched against the original commitment, so you can only reveal what you originally picked.

4. ESPN-style path-dependent scoring

   Picks are scored only if the feeder games that produced the matchup were also picked correctly. Lucky guesses on the championship don’t outweigh real forecasting skill across the bracket.

5. Automatic payout

   When the tournament ends, the prize pool is distributed to top finishers automatically by the contract. There is no “we’ll Venmo you next week.”

Why upfront commitment matters

The single biggest problem with on-chain bracket pools is Sybil attacks — one person spins up dozens of wallets, plays every plausible bracket, and guarantees themselves a top finish. Prediction Arena’s tournament structure eliminates this:

• Every entry costs the same fee. Spinning up 50 wallets costs 50 entries.
• Every entry must be a complete bracket, committed before the first game. You cannot wait to see how round one plays out and then “decide” your round-two picks across 50 wallets. Your picks are locked the moment the tournament starts.
• Path-dependent scoring punishes spread bets. Wallets that picked random brackets to “cover all outcomes” score badly across the board because none of their later picks are anchored by correct earlier picks.

The result is a tournament structure where the cheapest way to win is to actually be good at predicting the bracket, not the cheapest way to win is to spin up wallets.

Supported events

Prediction Arena tournaments support 4-team to 128-team brackets and scale to thousands of concurrent entrants per event. We focus on majors:

• Sports: football playoffs, basketball brackets, World Cup knockouts, tennis grand slams.
• Esports: League of Legends Worlds, Dota 2 TI, CS major playoffs, Valorant Champions.

The full live calendar is on the tournaments page.