# Play-Money Prediction Platforms

Where positions settle in a currency that does not come out again — no deposit, no withdrawal, no commission, and a price that has to be read differently.

*https://predictionmarkets.tools/collections/play-money*

## What settles in play money, and what that removes

`markets.settlement: play_money` is not "the same product without the money". Removing the money
removes a whole layer of the thing: there is no deposit, no withdrawal, no commission, no custody
and no regulator. It also removes the gatekeeping, which is why these platforms carry questions no
exchange would list, and why every card in this collection is open globally, open to US persons
and asks for no identity documents.

The catalogue makes half of that structural rather than editorial. A card that claims play-money
settlement and a non-zero taker or maker fee fails validation, because there is nothing to take a
cut of. [Manifold](https://predictionmarkets.tools/tools/manifold) says the same thing from inside its own source: the taker fee
constant and the flat trade fee are both zero.

The currency is the part readers get wrong most often. Manifold's mana is bought at a flat 100
mana per US dollar and, by its own terms, has no cash or redeemable value and cannot be cashed
out, sold, traded, transferred, gifted or exchanged — there is no charity route out either. So a
mana pack is a **purchase, not a deposit**, and the sweepstakes layer that briefly looked like an
exception is gone: Manifold announced the wind-down on 13 February 2025, stopped issuing sweepcash
immediately, gave holders until 28 March to redeem, and converted the remainder at 100 mana per
sweepcash.

Money does reach forecasters here, but always from the other direction, as a prize for a result
rather than a redemption of a balance. [Hypermind](https://predictionmarkets.tools/tools/hypermind) runs contests with a fixed
reward in euro or dollars, split among the forecasters who finish with positive performance and
paid as Amazon gift certificates, while the trading itself is in a virtual currency with no value
outside the game. [Prediki](https://predictionmarkets.tools/tools/prediki) calls it an Incentive: a sponsor pays a sum in advance
and it is apportioned at settlement by how early and how precisely you forecast — which also means
that the money arrives only when a sponsor does. [Metaculus](https://predictionmarkets.tools/tools/metaculus)
divides a fixed tournament pool in proportion to the squared sum of your Peer scores, and a
negative sum pays nothing.

## Half of these are not markets at all

This is the split to notice before picking one, and the flag that carries it is
`economics.liquidity_model`.

Three of these cards make a price. Manifold is an automated market maker with limit orders resting
on top of it, Hypermind runs an order book, Prediki moves a price as you invest Credits. A crowd
is taking sides and the number you read is the result.

The rest make **no price at all**. Metaculus, [Good Judgment Open](https://predictionmarkets.tools/tools/good-judgment-open),
[Fatebook](https://predictionmarkets.tools/tools/fatebook), [Confido](https://predictionmarkets.tools/tools/confido),
[Quantified Intuitions](https://predictionmarkets.tools/tools/quantified-intuitions) and the
[Social Science Prediction Platform](https://predictionmarkets.tools/tools/social-science-prediction-platform) ask you to state a
probability and score it against a proper scoring rule when the question resolves. Nothing is
bought, nothing is held, and there is no position to close early. They are in this collection
because the settlement field is the honest answer for a platform where nothing settles in money —
not because they are cheap versions of a venue.

That difference decides which one you want. A crowd price aggregates what many people believe,
weighted by how much of a consumable they were willing to put behind it. A proper score measures
*you*, and on Metaculus the design is explicit: everything is built on the log score, the Baseline
score compares you to a fixed benchmark, and Peer scores sum to zero by construction across
everyone on the same question.

## Who this is actually for

- **Learning calibration.** Quantified Intuitions' Pastcasting hands you questions that already
  resolved and scores you against the crowd of the day, so the feedback arrives in ninety seconds
  instead of six months. Fatebook is the same instinct pointed at your own work: write the
  prediction down in Slack or a browser, mostly privately, and collect a Brier score and a
  calibration chart over time.
- **Running it inside an organisation.** Confido is AGPL-3.0 and self-hosted, with rooms,
  tournaments and calibration curves, for a team whose questions cannot go on somebody else's
  site.
- **Testing a strategy, or code, before it costs anything.** Manifold has an order book, an API
  and automation, and being wrong costs mana. [The Manifold API](https://predictionmarkets.tools/tools/manifold-api) is a
  realistic rehearsal surface for the shape of code you would later point at a cash venue — and
  the rehearsal is missing the two things that will actually break it, which are fees and
  slippage against people who paid to be there.
- **Being somewhere the cash venues are not.** No deposit means no licence, no identity check and
  no geoblock. For a reader the [venues](https://predictionmarkets.tools/categories/prediction-market-venues) will not accept,
  this collection is the part of the catalogue that is open — with the understanding that what is
  open is the question and the score, not a payout.
- **Research.** The Social Science Prediction Platform asks what an unpublished study will find
  and ranks forecasters by error against the real estimate, which is a different exercise from
  everything above.

## The trap, stated precisely

A price on a thin cash market is unreliable because there is not enough size on it: the incentive
to correct a mispricing is real, but nobody large enough has shown up yet. **A play-money price
fails differently.** The incentive itself is missing. Mana goes in at a fixed rate and never comes
out, so moving a price costs whatever the currency cost and correcting one pays a number on a
profile. There is no pool of capital waiting for a mistake, and the question that is wrong can
stay wrong for as long as nobody finds it interesting.

Three consequences worth carrying into any number you read here:

- **Profit is not accuracy.** Someone who farms many small mispricings in thin questions and
  someone who is well calibrated on hard ones end up in very different places on a mana
  leaderboard, and the leaderboard cannot tell you which you are looking at.
- **The rules of the question are looser.** On Manifold anyone can open a question *and* resolve
  it; the recourse when a creator gets it wrong is a report to a moderator rather than a rulebook.
  On a cash venue, resolution is where the money is, and it is governed accordingly.
- **Incentive schemes bend the price towards the scheme.** Prediki apportions its sponsor money by
  how early and how precisely you forecast, which rewards moving first. Hypermind pays only
  forecasters who finish positive. Neither is hidden, and both are things the number is partly
  measuring.

None of which makes the prices worthless. Manifold's own platform-wide Brier score is a real
result and it is published rather than claimed. But it is a statement about thousands of resolved
questions in aggregate, and the question in front of you may have had four participants and a
creator who wrote the resolution criteria in one line.

Nothing here has been traded by this site with a funded account, because on these platforms there
is no such thing. Currency rules, prize mechanics and scoring formulas above are read from each
platform's own documentation and terms, and dated on the cards.

## Cards

- [Confido](https://predictionmarkets.tools/tools/confido.md) — Open-source forecasting workspace you host yourself, with a Brier score pointing upwards.
- [Fatebook](https://predictionmarkets.tools/tools/fatebook.md) — Write down what you think will happen, in Slack or a browser, and get scored on it.
- [Good Judgment Open](https://predictionmarkets.tools/tools/good-judgment-open.md) — Brier scores against the crowd, and the recruiting ground for Superforecasters.
- [Hypermind](https://predictionmarkets.tools/tools/hypermind.md) — Play money, a real order book, and a few thousand euro of prizes split by performance.
- [Manifold API](https://predictionmarkets.tools/tools/manifold-api.md) — Every read is keyless, the server is MIT-licensed, and the currency is play money.
- [Manifold](https://predictionmarkets.tools/tools/manifold.md) — Anyone can open a question, anyone can take a side, and the currency buys nothing.
- [Metaculus](https://predictionmarkets.tools/tools/metaculus.md) — Proper scoring and public track records on questions nobody can take a position in.
- [Prediki](https://predictionmarkets.tools/tools/prediki.md) — A wiki with a market attached — anyone writes the question, edits it, votes the result.
- [Quantified Intuitions](https://predictionmarkets.tools/tools/quantified-intuitions.md) — Forecast questions that already resolved, and learn in ninety seconds how wrong you were.
- [Social Science Prediction Platform](https://predictionmarkets.tools/tools/social-science-prediction-platform.md) — Forecast what a study will find, before it finds it, and be scored against the estimate.

## FAQ

### Can I ever get real money out of a play-money platform?

Not as a withdrawal, because there is no balance denominated in money to withdraw. Money can arrive from the other direction as a prize. Hypermind splits a fixed euro or dollar reward among the forecasters who finish a contest with positive performance and pays it as Amazon gift certificates; Prediki's Incentives are funded in advance by a sponsor and apportioned at settlement; a Metaculus tournament divides a fixed pool in proportion to the squared sum of your Peer scores. Each of those is a prize for a result, not a redemption of a balance.

### Why does no card here show a trading fee?

Because there is no money to take a cut of, and the validator enforces it - a card that sets settlement to play money and a non-zero taker or maker fee fails the build. Manifold makes the same point from inside its own open-source code, where the taker fee constant and the flat trade fee are both zero.

### Is a play-money price a real probability?

Sometimes, and for weaker reasons than a cash price. Manifold publishes its own calibration curve, and on 19 September 2026 the platform-wide figure was a Brier score of 0.17375 across all resolved markets - a claim about the aggregate, not about the question you happen to be reading. What is missing is the mechanism people cite when they trust a market price - nobody here is paid to correct a mispricing.

### Are these open to people the cash venues will not take?

Every card in this collection is listed as global, open to US persons and requiring no identity check, which is the direct consequence of there being no money in the system. It is also why a reader blocked from a cash venue often lands here. What you get is the questions and the scoring; what you do not get is a position with a payout.