Every order on RXN goes to Hyperliquid and settles there. It pays Hyperliquid’s fee, and RXN’s fee on top. Before you sign, the ticket shows the whole price of the order at your size: what it fills at, how far that is from the mid, and both fees.
The two fees
Hyperliquid’s. On its main perps, its fee schedule starts at 0.045% for a taker and 0.015% for a maker, and falls as an account trades more. HIP-3 markets have rates of their own, set with their deployers. The ticket uses your own rate on each market.
RXN’s. 2 bps (0.02%) on crypto and standard markets, and 0.5 bps (0.005%) on HIP-3 markets in growth mode, which their deployers set per market. A post-only limit order you place pays no RXN fee. A chase or a scale pays 1 bp on each post-only order it rests, or the market’s own rate where that is lower.
A worked example
A market order of $10,000 on a crypto perp, at Hyperliquid’s base rate: its fee is $4.50, and RXN’s is $2. Together, $6.50 before slippage. The ticket adds what the order would lose to the book on the way through, so the figure you see is the one you pay at that moment.
How the full price is counted
“All-in” walks the live order book level by level for your size: the average fill, its distance from the mid, Hyperliquid’s fee at your rate and RXN’s fee. A limit order that rests counts no slippage and the maker fee. Where the 20 levels Hyperliquid shows on each side can’t fill the size, the ticket says “book too thin” rather than guess.
How the fee is approved
Your wallet approves a ceiling for RXN’s fee once, 5 bps, and Hyperliquid never takes more than you approved. Each order then carries the rate for its market. Without that approval, orders go with no RXN fee: they are never refused for it.
Hyperliquid takes a builder fee per order, not per fill. A resting limit order pays RXN’s fee even when it fills as a maker; only a post-only order you place is sure to pay none.