Web app · Social Networking
Brierboard
Season-long forecasting tournaments, scored by Brier
Set a season, put YES/NO questions on the slate, have everyone give a probability, then resolve them and watch the Brier leaderboard sort out who actually knows anything. No money, no bets — free in your browser.
Stored in your browser only. Nothing you do in the web version is sent to our servers. Clear your browser data and it's gone — so export a backup from the in-app menu if you want to keep it.
In your browser
What you can do in Brierboard on the web
Seasons, not one-off bets
Each tournament has a start, an end, a roster of forecasters and a slate of questions everyone answers.
Real Brier scoring
(probability − outcome)² averaged over every resolved question — 0.000 perfect, 0.250 coin flip, 1.000 confidently wrong.
The forecast rail
Every question shows a 0–100% rail with each forecaster's call pinned on it, and a marker where the truth landed.
Calibration, not just wins
Buckets your forecasts by what you claimed and shows how often it actually happened — yours and the whole room's.
Season awards
Best forecaster, most overconfident (claimed confidence minus hit rate), sharpest and worst individual calls.
Nothing leaves the browser
No account, no money, no sync — export the seasons as JSON or the board as CSV whenever you want.
Screens
Every screen, rebuilt for the browser
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1
Tournaments
Your all-seasons Brier score, questions you have not called yet, and every season with its leader.
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2
Season
Standings, the full slate with each question's status, and the room's calibration.
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3
Question
The prompt, the forecast rail, everyone's probability, resolve YES/NO and the per-call Brier contribution.
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4
New tournament
Name the season, set its window, list the forecasters, and read how the scoring works.
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5
Board
One leaderboard across every season plus calibration charts and the season awards.
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6
Settings
Your name on the board, the no-money promise, JSON backup, CSV export, sample data and erase.
Try it with sample data: Loads three seasons — a Fall NFL slate, an Election Night pool and a Winter Markets & Tech season — with 15 questions, 10 of them resolved, and four forecasters with deliberately different calibration. You can start fresh at any time.
Ready? It's free.
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Questions
Is the web version of Brierboard free?+
Yes. Sign in with a free All Things AI account and use every screen — no subscription, no in-app purchases.
Where is my data stored?+
Only in this browser's local storage. Nothing you enter is sent to our servers, so we can't see it, back it up, or restore it. Clearing site data, a private window, or another device starts empty. Export a backup from the in-app menu to keep it.
Do I need an account?+
You can read about the app without one, but you must sign in to open it. Sign-in is free and takes a few seconds with Google.
How is the web version different from the Brierboard iPhone app?+
The iPhone app shares an invite deep link through AirDrop; in the browser one person keeps the board and enters everyone's probability, which is how a kitchen-table pool actually runs. There is no sync between devices — each browser holds its own seasons, so export the JSON if you want to move them. Resolution is whoever holds the board marking YES or NO; there is no consensus voting flow.