polymarket.event

stable Standard

One prediction event by slug (Gamma).

GET /v1/polymarket/event

What you get#

One Polymarket record in Onekey's unified shape, in data. If the record does not exist you get a 404 not_found and are not charged.

What it costs#

Standard · 1 credit for a fresh fetch, charged only when it succeeds.
Free when served from cache (0.2 credit for a cached response over 100 KB).
Free if the request is invalid (never charged) or the source fails or reports not found (refunded).

Parameters#

Name	Type	Required	Default	What it is	Constraints
`slug`	string	yes	(required)	Event slug	max 151 chars; must match `[a-z0-9][a-z0-9-]{0,150}`; trimmed, lowercased

Request#

curl "https://api.onekey.dev/v1/polymarket/event?slug=presidential-election-winner-2028" \
  -H "x-api-key: YOUR_API_KEY"

Try it

Add your key to run this call right here. No key? Get one free. The key stays in this tab.

Recorded response#

A real Polymarket response, recorded and returned in Onekey's shape. Fields the platform does not provide are null.

json

{
  "success": true,
  "data": {
    "entity": {
      "id": "31552",
      "name": "Presidential Election Winner 2028",
      "slug": "presidential-election-winner-2028",
      "description": "The 2028 US Presidential Election is scheduled to take place on November 7, 2028.\n\nThis market will resolve to the person who wins the 2028 US Presidential Election. Otherwise, this market will resolve to “No.”\n\nThe resolution source for this market is the Associated Press, Fox News, and NBC. This market will resolve once all three sources call the race for the same candidate. If all three sources",
      "date": "2029-01-21T04:59:00Z"
    },
    "media": {
      "thumbnailUrl": "https://polymarket-upload.s3.us-east-2.amazonaws.com/presidential-election-winner-2024-afdda358-219d-448a-abb5-ba4d14118d71.png"
    },
    "market": {
      "volume": 709818767.382539,
      "liquidity": 60031892.14583,
      "openInterest": 45702723.617331006,
      "volume24h": 96343.26259500001
    },
    "engagement": {
      "comments": 1037
    },
    "ext": {
      "active": true,
      "closed": false
    }
  },
  "metadata": {
    "platform": "polymarket",
    "endpoint": "event",
    "cached": false,
    "stale": false,
    "age_s": 0,
    "fetched_at": "2026-01-01T12:00:00+00:00",
    "credits_charged": 1,
    "request_id": "7f3a9c2e5b1d4c8fa2e6d0b9c4f18e37"
  },
  "error": null
}

Field mapping#

How this endpoint's source fields become Onekey's unified schema. Fields the source lacks come back as null.

Source path	Onekey field	Transform
`id`	`entity.id`	`toString`
`title`	`entity.name`	-
`slug`	`entity.slug`	-
`description`	`entity.description`	-
`image`	`media.thumbnailUrl`	`safeUrl`
`endDate`	`entity.date`	`toIsoDate`
`volume`	`market.volume`	`toNumber`
`liquidity`	`market.liquidity`	`toNumber`
`openInterest`	`market.openInterest`	`toNumber`
`volume24hr`	`market.volume24h`	`toNumber`
`commentCount`	`engagement.comments`	`toNumber`
`active`	`ext.active`	`toBoolean`
`closed`	`ext.closed`	`toBoolean`

Caching and freshness#

Fresh for about 30 minutes. Repeat calls in that window are served from cache and are free.
Between 30 minutes and 6 hours the cached copy is still served instantly and marked stale: true while Onekey refreshes it in the background.
If the source is down when a refresh is needed, the last copy can be served for up to 1 day more (marked stale).
A "not found" is remembered for 5 minutes and is free.
The cache is shared across all customers, which is what keeps repeat calls cheap.

What can go wrong#

Status	Code	What to do
401	`unauthorized`	Check the `x-api-key` header.
402	`insufficient_credits`	Add credits; your balance must cover the price.
404	`not_found`	That record does not exist. Free; do not retry.
422	`invalid_params`	Fix the parameters using the table above. Free.
429	`rate_limited`	Wait `Retry-After` seconds, then retry.
502	`upstream_error`	The source failed. Refunded; retry with backoff.

See Errors for the full list and retry guidance.

Status: stable (verified against the live source).