Polymarket prediction market data endpoints, plus API documentation and monitoring.

Resources & endpoints

Polymarket Markets

Market Open Interest

Returns the open-interest time series for a market. Open interest is the USDC collateral locked into conditional token positions. It increases on splits (deposit USDC to mint Yes+No pairs) and decreases on merges (return pairs to withdraw USDC) or redemptions.

Provide exactly one of condition_id or market_slug.

GET

https://api.pinax.network/v1/polymarket/markets/oi

Requires bearer token — sign in to inject your team’s key.

Optional parameters

Name	Type	Description
condition_id query	string	e.g. 0x9708334534b504e2025a5a6af92f8600808c10be577e5066f920c40625fbec16
market_slug query	string	e.g. will-bitcoin-reach-150k-in-january-2026
interval query	Enum · 8	The interval* for which to aggregate price data (1-minute, 5-minutes, 10-minutes, 30-minutes, hourly, 4-hours, daily or weekly). *Plan restricted. 1m5m10m30m1h4h1d1w
start_time query	Datetime	UNIX timestamp in seconds or date string (e.g. "2025-01-01T00:00:00Z", "2025-01-01", ...).
end_time query	Datetime	UNIX timestamp in seconds or date string (e.g. "2025-01-01T00:00:00Z", "2025-01-01", ...).
limit query	integer	Number of items* returned in a single request. *Plan restricted.
page query	integer	Page number to fetch. Empty `data` array signifies end of results.

Response

200 OK

{
  "data": [
    {
      "timestamp": "2025-04-04 00:00:00",
      "net_open_interest": 43835.62,
      "split_amount": 292320.96,
      "merge_amount": 248485.34,
      "split_count": 989,
      "merge_count": 172,
      "transactions": 1161,
      "unique_stakeholders": 14,
      "market": {
        "condition_id": "0x39e227f0e4a6c0a7b282d77ae0e7d247d0cc4b8e69a348e853442bbd4db10f6a",
        "market_slug": "bitcoin-above-86000-on-april-4",
        "token_id": null,
        "outcome_label": null,
        "closed": false
      }
    }
  ]
}