Manifold Markets API Guide (2026): Endpoints, Keys & Limits

Manifold’s API gives free access to its play-money prediction markets: market lists, probabilities, bets, users and comments. Reads need no account; placing bets, creating markets and resolving them need an API key. Manifold labels the API alpha, so endpoints can change. This guide covers the essentials from Manifold’s API documentation, checked October 2026.

The API at a glance

Item	Detail
Base URL	`https://api.manifold.markets/v0/`
Auth	Header `Authorization: Key {your key}`; reads need none
Rate limit	500 requests per minute per IP
Status	Alpha: “things may change or break at any time”
Money	Mana (play money); see Manifold

The older manifold.markets/api address is being retired, so point existing code at api.manifold.markets.

Reading markets (no key needed)

The newest markets, one at a time:

curl "https://api.manifold.markets/v0/markets?limit=1"

We ran that request on October 28, 2026 and got JSON back. Other useful reads:

GET /v0/market/[marketId]: one market, with its answers.
GET /v0/slug/[marketSlug]: look a market up by the slug in its URL.
GET /v0/search-markets?term=…: search, with sort, filter and contractType options (default 100 results, up to 1,000).
GET /v0/market/[marketId]/prob: the current probability, or one per answer for multiple-choice markets. GET /v0/market-probs takes up to 100 ids at once.
GET /v0/bets and GET /v0/comments: filter by user or market (up to 1,000 per call).
GET /v0/user/[username], /v0/users, and /v0/me (needs a key).

GET /v0/markets returns up to 1,000 markets per request (500 by default).

Getting a key

Open your Manifold profile, click edit, and press the refresh button next to the API key field. Each account has at most one key, and refreshing it again invalidates the old one. Send it on every authenticated request:

curl -H "Authorization: Key YOUR_KEY" "https://api.manifold.markets/v0/me"

Writing: bets and markets

POST /v0/bet: place a bet or limit order, with amount, contractId, outcome (YES by default) and an optional limitProb between 0.01 and 0.99. Set dryRun to simulate without betting.
POST /v0/bet/cancel/[id]: cancel an open limit order.
POST /v0/market: create a market. Manifold charges M$50 for a binary market, M$250 for pseudo-numeric and M$25 per answer for multiple choice.
POST /v0/market/[marketId]/resolve: resolve a market you created. Binary markets take YES, NO, MKT or CANCEL.

Comments posted through the API cost M$1 each.

Terms worth knowing

Bots, automated trading and integrations are allowed under Manifold’s terms.
Scraping the site other than through the API, or getting round the rate limit (for example with several IPs), isn’t.
Training commercial AI or machine-learning models on the data needs a licence from Manifold ([email protected]). Academic, personal and non-commercial use is allowed.

FAQ

Is the Manifold API free?

Yes. Reading is free with no key; writing needs a free key from your profile. Actions like creating markets cost mana, Manifold’s play money.

What’s the Manifold API rate limit?

500 requests per minute per IP address.

Can I trade real money through it?

No. Manifold uses play money, and mana can’t be cashed out.

Sources: Manifold API documentation, checked October 28, 2026, plus our own test request that day.