Prediction markets API

Many prediction markets' state and live outcome prices

Up to 25 prediction markets in one request: each one's lifecycle, windowed stats and the live price of each outcome.

POST/api/external/prediction/prediction-market-batch

Get a free API key Try it in the API reference

What it returns

The prediction-market answer for many markets in one request, addressed by the ids from GET /prediction/prediction-markets. Each result is exactly what prediction-market answers for that market, with the same caveats on every field — including the all-null answer for a well-formed id nobody recognises, which is a result, not an error. POST, because the list is the subject: it can run past what a URL comfortably holds, and a body keeps a watch list out of every proxy log between the caller and this service.

Chains

This endpoint is not tied to a chain: it takes no chain in its request.

Request

Send your key in the x-dex-data-key header. Replace each <placeholder> with a real value.

curl -X POST -H "x-dex-data-key: $DEXDATA_API_KEY" \
  -H "content-type: application/json" \
  -d '{"subjects":["<subjects>"]}' \
  "https://api.dexdata.io/api/external/prediction/prediction-market-batch"

Parameters
Parameter	Description
`subjects` body · string[] · optional	Prediction market ids — never a token mint or contract address. Between 1 and 25, each sent once.

Response fields

A JSON response. Every field is always present; null means the value could not be established, never zero.

Response fields of Many prediction markets' state and live outcome prices
Field	Type	Description
`results`	object[]	One entry per requested subject, in the order they were sent.
`results[].subject`	string	The subject exactly as it was sent.
`results[].result`	object \| null	What the single-subject endpoint answers for this subject. `null` only when `error` is set.
`results[].result.id`	string \| null
`results[].result.protocol`	string \| null	The venue this market trades on, e.g. "POLYMARKET" or "KALSHI".
`results[].result.eventId`	string \| null	The event this market belongs to, or null for a standalone market.
`results[].result.question`	string \| null
`results[].result.label`	string \| null	A short label for this market within its event, when it has a parent event.
`results[].result.outcomeIds`	string[] \| null	The two outcome ids — pass one to `GET /prediction/prediction-outcome-order-book`.
`results[].result.outcomeLabels`	string[] \| null
`results[].result.categories`	object[] \| null
`results[].result.categories[].name`	string \| null
`results[].result.categories[].slug`	string \| null
`results[].result.categories[].subcategories`	unknown[] \| null
`results[].result.resolution`	object \| null	Null until the market resolves.
`results[].result.resolution.result`	string \| null
`results[].result.resolution.source`	string \| null
`results[].result.createdAt`	number \| null	Unix seconds this market was created.
`results[].result.opensAt`	number \| null	Unix seconds the market opened for trading.
`results[].result.closesAt`	number \| null	Unix seconds trading closes.
`results[].result.resolvesAt`	number \| null	Expected resolution time, Unix seconds.
`results[].result.resolvedAt`	number \| null	Actual resolution time, Unix seconds — null while unresolved.
`results[].result.networkId`	number \| null	The on-chain settlement network id (e.g. 137 for Polygon/Polymarket) — null for a Kalshi market, which has none.
`results[].result.exchangeAddress`	string \| null	The on-chain exchange contract, when this market settles on-chain.
`results[].result.winningOutcomeId`	string \| null	Null until the market resolves.
`results[].result.lifecycle`	object
`results[].result.lifecycle.ageSeconds`	number \| null
`results[].result.lifecycle.expectedLifespanSeconds`	number \| null
`results[].result.lifecycle.timeToResolutionSeconds`	number \| null
`results[].result.lifecycle.isResolved`	boolean \| null
`results[].result.lifecycle.winningOutcomeId`	string \| null
`results[].result.allTimeVolumeUsd`	number \| null	Lifetime trading volume, USD.
`results[].result.statsHour1`	object
`results[].result.statsHour1.volumeUsd`	number \| null	Trading volume over the window, USD.
`results[].result.statsHour1.trades`	number \| null	Number of trades over the window.
`results[].result.statsHour1.uniqueTraders`	number \| null	Distinct trading accounts over the window — null on venues that do not report it (measured: Kalshi).
`results[].result.statsDay1`	object
`results[].result.statsDay1.volumeUsd`	number \| null	Trading volume over the window, USD.
`results[].result.statsDay1.trades`	number \| null	Number of trades over the window.
`results[].result.statsDay1.uniqueTraders`	number \| null	Distinct trading accounts over the window — null on venues that do not report it (measured: Kalshi).
`results[].result.priceObservedAt`	number \| null	Unix seconds the outcome prices below were observed at.
`results[].result.outcomePrices`	object[]	One entry per outcome. Empty for an unrecognised market id.
`results[].result.outcomePrices[].outcomeId`	string \| null
`results[].result.outcomePrices[].lastTradePriceUsd`	number \| null	Last traded price, USD (0-1 for a binary market).
`results[].result.outcomePrices[].bestBidUsd`	number \| null	Best resting bid, USD — null when there is none (a literal `"0"` in the source data is read as absent, never a real zero price).
`results[].result.outcomePrices[].bestAskUsd`	number \| null	Best resting ask, USD — null when there is none, same reasoning as `bestBidUsd`.
`results[].result.outcomePrices[].bookLiquidityUsd`	number \| null	Liquidity currently backing the order book for this outcome, USD.
`results[].error`	string \| null	`null`, or `unavailable` when no source could be reached for this subject — retry it. A subject nobody has data for is NOT an error: its `result` says so.

Price per call

Every call: 422 creditsbase; varies with subjects

Charged only when the call succeeds. Prices as of 2026-10-30; the current ones are always in the API reference.

One prediction market's state and live outcome prices
The same answer for one market.
Prediction markets, ranked by volume, liquidity or open interest
A ranked page of prediction MARKETS -- the tradeable instrument on an event. Use it to find a market id; per-outcome prices come from the single-market read.
One prediction-market outcome's live order book
What is resting on one outcome's book right now, bid and ask. A different question from who already holds the outcome token.
Holder balances for one outcome token of one prediction market
Who holds the outcome token, and how much. A different question from the order book: position already taken, not orders waiting to be filled.
Latest trades and redemptions on one prediction market
The tape of one market: who traded which outcome, at what price and size, newest first, with redemptions once it resolves.
Who traded one prediction market, and how each trader did on it
The traders of one market ranked by volume, realized PnL or activity, with each one's position, entry price and PnL per outcome.

Start building with DexData today

Sign in, create a key and make your first call in a minute. Free credits every month, and you only pay for calls that succeed.

Get a free API key