Glossary

Corridor — A currency pair you can swap, like cNGN ↔ USDT.

Effective rate — The all-in exchange rate for a specific swap, with the taker fee and the filler's spread already included. What you compare against an OTC or P2P quote.

Filler — An operator (usually a bot) who quotes both sides of a corridor's order book, earning the spread when traders fill their orders.

Filler order book — The off-chain book of signed limit orders. Fillers quote into it and traders' resting limit orders sit in it as first-class liquidity; your swap matches against the whole book, best price first.

Instant swap — A swap that executes now at the book's best available price. The default mode of the Swap interface.

Limit order — A signed commitment to trade a specific amount at a specific price, valid until it expires, is cancelled, or is replaced. Gasless to post; fills exactly once. Fillers post them as quotes, and traders post them to name their own price (see How to place a limit order).

Settlement contract — The on-chain reactor (UniswapX LimitOrderReactor) that verifies an order's signature and executes a matched swap in one transaction.

Taker fee — The protocol fee on a swap, included in the quoted rate. Set per chain by the on-chain SellFirstFeeController: 1 bps (0.01%) on BSC and Celo, 5 bps (0.05%) on Ethereum.

Trader — A user swapping one stablecoin for the other through the Swap interface.