Manifold

What it is

A prediction market where anyone can open a question in about thirty seconds, anyone can take a side of it, and the person who opened it decides how it resolves. Everything is denominated in mana, written M, which Manifold's own documentation describes in four words as play-money currency that cannot be converted to cash.

That is the whole product and also the whole argument about it. Removing money removes the gatekeeping: there is no deposit, no licence, no market-listing committee, and consequently there are tens of thousands of questions on subjects no exchange would ever list. It also removes the mechanism everyone cites as the reason a market price means anything. Manifold's answer is to publish its own calibration curve — on 19 September 2026 the platform-wide figure on its calibration page was a Brier score of 0.17375 — and to argue in public that the number holds up.

Read the denominator, because the page publishes one and it is not "every market". The method described beside the figure samples 2% of all past trades every hour, on resolved binary questions with fifteen or more traders, and the stated sample was 98,000 trades. It is trade-weighted rather than time-weighted, which Manifold notes itself, adding that accuracy may be better than the chart shows because large miscalibrated trades are usually corrected immediately. The page does not say whether the Brier figure covers that same sample or something wider. Read on 21 September 2026.

That figure has no unit printed on it, and Brier has two conventions in circulation. One sums the squared error over both outcomes of a binary question and is bounded at 2; the other scores a single outcome and is bounded at 1. They differ by a factor of two on every number, so 0.17375 means two quite different things depending on which Manifold used, and its calibration page does not say. Read against the definition this catalogue uses on the forecasting platforms page, which is the two-outcome one, it would be a strong number; read the other way it is an ordinary one. Do not rank it against a score from another platform without settling that first.

Pricing is an automated market maker: you trade against a curve rather than against a queue of other people's orders, with limit orders resting on top of it that other traders fill when they push the probability through your level. Creating a question subsidises its own liquidity pool out of the creation cost.

What mana actually is

Worth being precise, because this is the field readers get wrong. Mana is bought from Manifold at a flat 100 mana per US dollar — the smallest credit-card pack is $5 for M500 — and it flows the other way not at all. The terms say it has no cash or redeemable value and cannot be cashed out, sold, traded, transferred, gifted or exchanged, on the site or elsewhere. There is no longer a charity-donation route out either.

So the honest description is a consumable, not a currency. You can spend mana on positions, on creating questions, on subsidising someone else's liquidity, and on Manifold's own digital goods. You cannot get a dollar back out of it, and a leaderboard denominated in it is a leaderboard of skill at Manifold, which overlaps with but is not the same as being right.

Loans complicate this slightly. A free daily loan against your open positions is interest-free and available to everyone; a margin loan, which requires a paid membership, accrues 0.03% interest per day, is deducted from your proceeds when a position closes whether or not your balance covers it, and can take your balance negative. In mana, but negative.

The sweepcash episode

Between September 2024 and March 2025 Manifold ran a parallel sweepstakes currency, sweepcash, which eligible users could redeem for cash. It is gone. Manifold announced the wind-down on 13 February 2025, halted new sweepcash issuance from purchases, signups and streaks immediately, resolved sweepstakes markets closing after 3 March to their current probability, gave users until 28 March to cash out or donate, and converted everything left at 100 mana to 1 sweepcash. The stated reason was that sweepstakes had not met usage goals and were pulling attention away from the core platform. Anything you read describing Manifold as a real-money venue is describing that five-month window.

Availability

Open worldwide, free to join, and no identity check to use it. The terms are the usual California-company shape — the site is not tailored to any jurisdiction, and anyone accessing it from elsewhere does so on their own initiative. Minimum age is 13, with parental permission required for minors.

Two places where identity verification does appear, and neither is a condition of forecasting. Verifying identity unlocks a larger starting mana balance and a referral bonus. And Manifold runs prize drawings with real prizes, which carry their own geographic eligibility rules, no-purchase terms, and an identity check through a third-party provider before a prize is paid. Read the drawing's own rules rather than assuming the platform's openness carries over to them.

Pricing

Free, with two things for sale, neither required.

Mana packs are the one with a published number, and it is published in Manifold's own repository: a flat 100 mana per US dollar on credit-card purchases with no purchase bonus, in packs of $5, $25, $100 and $1,000. Since mana cannot come back out, this is a purchase and not a deposit.

Memberships — Plus, Pro and Premium — are the second, and they are what gates margin loans and higher leverage. They are not bought with dollars: the shop configuration in Manifold's repository prices them at M500, M2,500 and M10,000 for thirty days, alongside quest-reward multipliers and a shop discount. Mana is the only thing here you can spend money on.

Trading the question markets is free. The taker fee constant and the flat trade fee in the open-source code are both zero, which is the answer the play-money design forces anyway. The perpetuals are the exception and the one place a fee exists: opening a position costs 10 basis points of notional on all 27 live perp markets on 19 September 2026, closing costs nothing, and the fee goes into that market's backing pool rather than to Manifold. Trades authenticated with an API key are charged separately, 10 to 30 basis points across those markets — a separate rate the code introduces after two episodes in August 2026 in which bots trading a stale oracle mark drained the Bitcoin perp pools.

Markets & resolution

Every subject, because anybody can list anything: elections, sports, macro and equity prices, AI capability and safety, awards and reality television, personal accountability questions, and a large tail of questions about Manifold itself. Market types include binary, multiple choice with independent or summing answers, numeric, polls, bounty questions, and perpetuals — leveraged long or short positions on a live number with no expiry, priced off an oracle feed rather than off a crowd, which is a different product wearing the same currency.

Resolution is the part to understand before trusting a price here. The creator resolves their own question. Manifold says so plainly and treats it as a design choice, encouraging clear criteria written in advance and stepping in only in exceptional circumstances. Moderators can overturn a resolution, and re-resolve for abuse, misresolution or technical failure, after a user report. Resolving to N/A cancels a question and is restricted to moderators and staff. There is also a PARTIAL resolution, where the creator picks a percentage rather than an outcome.

Compare that with a venue, where resolution is the operator's obligation against a named source and money is sitting on the answer, and with Metaculus, where staff resolve against published criteria and annul what cannot be evaluated. On Manifold the resolver is a stranger with no stake in being consistent, which is the standing risk on any Manifold price and the reason the creator's track record is worth a look before taking a side.

Integrations

The API is genuinely public in the way Metaculus's no longer is: read endpoints need no authentication, writes need a key, and the documented rate limit is 500 requests per minute per IP. There is a real-time websocket server for market, trade and other event updates, which needs a ping every 30 to 60 seconds or the connection is dropped. Bots and automated trading are explicitly permitted; scraping outside the API is not.

Free bulk dumps of bets, markets and comments are offered as zipped JSON for personal and non-commercial use — and they are stale. The data page states the dumps were last updated on 6 July 2024. Anything more recent, or any commercial or model-training use, goes through a data licence.

The platform is MIT-licensed and the repository was last pushed to on 18 September 2026. Manifold does not offer it as a self-hosted product, and nothing in the docs describes running your own instance.

Limitations

Creator resolution is the one to weigh. A market is only as good as the person who wrote it, and the recourse when they get it wrong is a report to a moderator rather than a rulebook.

The public data dumps have not moved since July 2024, so a research project that needs history either lives on the API and its rate limit or pays for a licence.

Mana profit is the headline number on a profile, and profit is not accuracy. Someone who trades many small mispricings in thin markets and someone who is well calibrated on hard questions end up in very different places on a mana leaderboard, and the leaderboard cannot tell you which you are looking at. The platform-wide Brier score is a claim about Manifold as an aggregate, not about any individual on it.

The perpetuals are a second product on the same balance and they do not behave like the rest of the site. Positions carry leverage — capped at 3x on eighteen of the 27 live markets, 10x on six and 100x on three — they can be liquidated, they price off an oracle feed rather than off the crowd, and they are the only thing here that charges a fee. A calibration argument about Manifold's question markets says nothing about them.

And the currency does not leave. Buying mana is buying a consumable; the terms are unusually blunt about that, and it is the right way round to read them.

Alternatives

Metaculus if you want a proper scoring rule and a record that means something outside the site — fewer questions, slower, scored rather than traded. Good Judgment Open if you want to be ranked against a crowd on geopolitical questions by Brier score, with a route to professional work at the end of it.