CLOB
Central Limit Order Book — Polymarket's matching engine for limit + taker orders.
Definition
A CLOB (Central Limit Order Book) is a matching engine that aggregates resting limit orders on each side and matches incoming takers against the best resting prices. Polymarket runs its own CLOB at clob.polymarket.com. Orders are signed off-chain and settled on Polygon via the Conditional Tokens Framework.
In practice
A GTC (Good-Til-Cancelled) maker order rests on the book and earns rebates when matched. A FOK (Fill-Or-Kill) taker order matches immediately at the best available price or cancels. Bot developers typically combine both to control fee exposure.