According to CoinMeta, GMX has introduced the Builder Fees mechanism in Solana. Developers can charge fees from users' orders by building trading interfaces or tools. Developers need to publish the fee rates on the blockchain, and traders must sign off to these rates when placing orders. The fees are added to the standard transaction costs and are calculated based on changes in positions. For example, if a position increases by $1,000 and the fee rate is 0.01%, a fee of $0.10 will be charged and settled into the developer's designated wallet. This mechanism applies to market-price and limit-order increases, decreases, and stop-loss reductions, but it does not apply to exchanges, liquidations, or ADL.