Builder codes

What a builder code is

Hyperliquid lets an app attach a builder address and a fee to the orders it sends. The user approves a maximum rate once with ApproveBuilderFee; each order then names the builder and a fee up to that maximum, and Hyperliquid credits the fee to the builder when the order fills. The cap for perps is 0.1%. HyperWafer asks you to approve 0.05% and charges your bin's rate.

The order field

{"type":"order","orders":[{"a":110002,"b":true,"p":"182.5","s":"1","r":false,"t":{"limit":{"tif":"Gtc"}}}],
 "grouping":"na","builder":{"b":"0x72181a1fda6e86d3464b7be150b4923ca82d309e","f":10}}

f: 10 is 0.01%, Bin 1. Check what you approved with the info request {"type":"maxBuilderFee","user":"0x...","builder":"0x..."}.

Before trading opens

Hyperliquid accepts a builder only once its account holds at least 100 USDC in perps account value. Until the terminal sees that through the info API, the order ticket reads "Trading opens soon" and sends nothing; prices, books, account views, the benchmark and the leaderboard work as usual. Every order the terminal sends carries the builder code.