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Market Open Interest

GET/v1/polymarket/markets/oi

Returns 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 one of condition_id or market_slug.

Query Parameters

ParameterDescriptionValue
condition_id
string
    market_slug
    string
      interval
      string

      The interval* for which to aggregate price data (1-minute, 5-minutes, 10-minutes, 30-minutes, hourly, 4-hours, daily or weekly).
      *Plan restricted.

      • Default value: 1d
      • Accepted values: 1m, 5m, 10m, 30m, 1h, 4h, 1d, 1w
      1d
      start_time
      string

      UNIX timestamp in seconds or date string (e.g. "2025-01-01T00:00:00Z", "2025-01-01", ...).

        end_time
        string

        UNIX timestamp in seconds or date string (e.g. "2025-01-01T00:00:00Z", "2025-01-01", ...).

          limit
          integer

          Number of items* returned in a single request.
          *Plan restricted.

          • Default value: 10
          • Minimum value: 1
          • Maximum value: 1000
          page
          integer

          Page number to fetch.
          Empty data array signifies end of results.

          • Default value: 1
          • Minimum value: 1
          • Maximum value: 767465558638

          Potential Responses

          StatusDescription
          200

          Successful Response

          400

          Client side error

          401

          Authentication failed

          403

          Forbidden

          404

          Not found

          500

          Server side error