/v4/data/prediction/markets/{id}/orderbook

100 credits per API call

Current orderbook snapshot for one side of a market. The orderbook is per-outcome — pass side=yes or side=no to choose which outcome's book you want. Returns top-of-book through to depth levels of bids and asks, with a computed quoted-liquidity figure within 1% and 5% of the midpoint.

Other notes

• side is required.
• hash is a content fingerprint of the book snapshot useful for ETag-style change detection on poll. Populated on Polymarket; null on Kalshi (no equivalent upstream field).
• Returns 404 when the market does not exist on either platform.