# hooks-fee-prereq

Hook API [etxn_fee_base](https://xrpl-hooks.readme.io/v2.0/reference/etxn_fee_base) estimates a transaction fee, based on (i.a.) the number of reserved transactions, so a call to it must be preceded by a call to [etxn_reserve](https://xrpl-hooks.readme.io/v2.0/reference/etxn_reserve).

[Read more](https://xrpl-hooks.readme.io/v2.0/docs/hook-fees)
