Prediction markets API

Which prediction market is on this venue page?

Resolve a prediction market page slug (or a ticker) to the market: its venue id, title, event, outcome labels and close date. Identity only, no prices or volume.

GET/api/external/prediction/prediction-market-by-slug

Get a free API key Try it in the API reference

What it returns

The market a venue page slug names — the last path segment of the market's page, e.g. mlb-wsh-det-2026-09-23, or a kalshi ticker in any case — with its id in the venue's own id space, its title, event, outcome labels and dates. Identity only, not prices, volume or trading status: read closesAt to tell a live market from a finished one. The ids are the ones prediction-search returns. An unknown slug answers market: null. No chain and no subject.

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 -H "x-dex-data-key: $DEXDATA_API_KEY" \
  "https://api.dexdata.io/api/external/prediction/prediction-market-by-slug?slug=<slug>"

Parameters
Parameter	Description
`slug` query · string · required	The market's page slug: letters, digits, `.`, `_` and `-`, at most 200 characters.

Response fields

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

Response fields of Which prediction market is on this venue page?
Field	Type	Description
`slug`	string	The slug asked for, trimmed.
`market`	object \| null	The market whose page has this slug; `null` when no market has it.
`market.exchange`	string	The venue, lowercase, e.g. `kalshi` or `polymarket`. Open set: new venues can appear.
`market.id`	string	The market's id in its venue's own id space: the ticker on `kalshi`, the condition id on `polymarket`.
`market.title`	string	The market's question.
`market.label`	string \| null	The market's label inside its event, e.g. `Green Bay`. Null when it has none.
`market.slug`	string \| null	The market's URL slug on its venue, as the venue writes it.
`market.kind`	string \| null	The product shape, e.g. `binary`. Open set.
`market.eventId`	string \| null	The event this market belongs to, in the venue's own id space (the `id` of an event row of `prediction-search`). Null for a standalone market.
`market.outcomes`	string[]	The outcome labels, e.g. `Yes`, `No`. No prices.
`market.createdAt`	string \| null	ISO-8601 UTC, when the market was listed.
`market.closesAt`	string \| null	ISO-8601 UTC, when trading closes or closed. A date in the past means the market is no longer trading.

Price per call

Every call: 18 credits

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

Which prediction markets, events or traders match this text?
Find markets by free text when the exact slug is not known.
Which prediction-market categories carry the most volume on each venue?
Per venue, each category tag with its market count and all-time volume, highest first. Volume is in the venue's own unit: contracts on kalshi, USD on polymarket.
Which sports leagues can I find prediction markets for?
The sports leagues a prediction venue lists markets under: league code, the venue's own league, series and tag ids, settlement source and logo.
What did this crypto up-or-down window open and close at?
The reference open ("price to beat") and close of one 5-minute or 1-hour crypto window, e.g. BTC 14:30–14:35; the close is null until the window settles.
How did the price move across this crypto up-or-down window?
The reference price path across one 5-minute, 15-minute or 1-hour crypto window, with its first and last price; the 15-minute open and close come from here.
What is a prediction market's open interest, and how many holders and trades?
Contracts open right now and lifetime volume (Kalshi), or lifetime volume, distinct holders and trade count (Polymarket), for one market. Counts, not USD.

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