API reference

Bulk prices

Latest quotes for up to 100 contracts in one request. Ids TPM does not track come back in unresolved instead of failing the call.

When to use it

Refresh a watchlist or portfolio every minute or so.
Get stream ids for many contracts at once before opening the WebSocket.

For prices that change all the time, subscribe on the WebSocket instead of polling.

GET/api/public/v1/pricesAPI key required

Get latest quotes

Each row has the same quote, freshness and stream ids as event detail.

Parameters

Name	In	Type	Required	Default	Description
ids	query	string	Yes	—	Comma-separated `venue:contract_id` pairs, up to 100. Kalshi: market ticker. Polymarket: condition id.

Request

curl -s 'https://api.thepredictionmarkets.com/api/public/v1/prices?ids=kalshi:KXPRESNOMD-28-GN,polymarket:0x0f49db97f71c68b1e42a6d16e3de93d85dbf7d4148e3f018eb79e88554be9f75,kalshi:KXNOTREAL-99' \
  -H 'X-API-Key: tpm_demo_key_authorized_2026'

Response

Example 200 response. Values are illustrative and change over time.

200 OK

{
  "data": [
    {
      "id": "kalshi:KXPRESNOMD-28-GN",
      "venue": "kalshi",
      "contract_id": "KXPRESNOMD-28-GN",
      "title": "Gavin Newsom",
      "market_id": "KXPRESNOMD-28",
      "event_slug": "democratic-presidential-nominee-2028",
      "quote": {
        "probability": 0.16,
        "best_bid": 0.16,
        "best_ask": 0.17,
        "spread": 0.01,
        "source": "live",
        "observed_at": "2026-10-21T08:38:56Z",
        "age_seconds": 3,
        "freshness": "live"
      },
      "stream": {
        "provider": "kalshi",
        "market_id": "KXPRESNOMD-28-GN",
        "outcome_id": "yes"
      }
    },
    {
      "id": "polymarket:0x0f49db97f71c68b1e42a6d16e3de93d85dbf7d4148e3f018eb79e88554be9f75",
      "venue": "polymarket",
      "contract_id": "0x0f49db97f71c68b1e42a6d16e3de93d85dbf7d4148e3f018eb79e88554be9f75",
      "title": "Gavin Newsom",
      "market_id": "democratic-presidential-nominee-2028",
      "event_slug": "democratic-presidential-nominee-2028",
      "quote": {
        "probability": 0.1635,
        "best_bid": 0.163,
        "best_ask": 0.164,
        "spread": 0.001,
        "source": "snapshot",
        "observed_at": "2026-10-21T08:37:22Z",
        "age_seconds": 94,
        "freshness": "fresh"
      },
      "stream": {
        "provider": "polymarket",
        "market_id": "0x0f49db97f71c68b1e42a6d16e3de93d85dbf7d4148e3f018eb79e88554be9f75",
        "outcome_id": "54533043819946592547517511176940999955633860128497669742211153063842200957669"
      }
    }
  ],
  "unresolved": [
    "kalshi:KXNOTREAL-99"
  ]
}

Response fields

Field	Type	Description
data[].id	string	The id you asked for, `venue:contract_id`.
data[].venue, contract_id	string	Venue and contract.
data[].title	string	The outcome title.
data[].market_id	string	The venue listing the contract belongs to.
data[].event_slug	string \| null	The TPM event.
data[].quote.probability	number \| null	The displayed price as a probability from 0 to 1, using the venue's own display rule. 0.16 means a 16% implied chance.
data[].quote.best_bid	number \| null	Highest price someone will pay for Yes right now.
data[].quote.best_ask	number \| null	Lowest price someone will sell Yes for right now.
data[].quote.spread	number \| null	`best_ask - best_bid` on this venue (not the cross-venue gap).
data[].quote.source	"live" \| "snapshot"	`live`: from the venue's WebSocket feed. `snapshot`: from TPM's REST poll of the venue.
data[].quote.observed_at	string \| null	When this price was last known to be current (UTC).
data[].quote.age_seconds	integer \| null	Seconds since `observed_at`.
data[].quote.freshness	string	`live`, `fresh`, `aging`, `stale` or `unknown`. See freshness.
data[].stream	object \| null	WebSocket ids `{provider, market_id, outcome_id}`.
unresolved	string[]	Requested ids TPM does not track.

Errors

HTTP	Code	When
400	validation.invalid_id	An id is not a `venue:contract_id` pair.
400	validation.too_many_ids	More than 100 ids.
400	validation.invalid_parameter	`ids` is missing.
401	auth.missing_key	No `X-API-Key` header was sent.
401	auth.invalid_key	The key is wrong or was revoked.
429	rate_limit.per_second	Too many requests this second. Wait for `Retry-After`.

400 validation.invalid_id

{
  "error": {
    "code": "validation.invalid_id",
    "message": "'foo' is not a `venue:contract_id` pair.",
    "request_id": "0f8969a6-0968-4d7c-9cbb-de379e8c19c4"
  }
}

All codes are listed on the errors page.

Try it

Runs a live request from your browser. Pre-filled with the shared demo key (5 requests per second for everyone); paste your own key for steadier results.

Request URLX-API-Keyids*query

HTTP: —Time: —Rows: —Remaining this second: —Request: —

Press Send to run this request.

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One key gives you Kalshi and Polymarket events, prices with freshness, price history, cross-venue gaps and the live quotes WebSocket.

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