Send component architecture

Send component is a mix of hooks and redux.

Hooks are used to control and validate form fields using react-hook-form library

Redux is used for persistent data like drafts, fiatRates, settings etc...


Entry point of send form component. Implements useSendForm hook by passing Redux props to it.


Hook and set of sub-hooks The whole logic of send form pre/post validation, working with field (recalculation), async transaction composing and sending


Called from useSendForm hook. A set of operations with @trezor/connect and post validation (see: Transaction signing)


Storing transaction drafts and temporary data used in TransactionReviewModal

Transaction compose process

Validation of react-hook-form state occurs in React.useEffect so potential errors are available after render tick.

In order to work with properly validated state useSendFormCompose.composeRequest also needs to be handled in React.useEffect after render tick.

Every networkType has own sendFormActions.composeTransaction method

  • sendFormActionsBitcoin does calculation using @trezor/connect
  • sendFormActionsEthereum does calculation locally, custom feePerUnit is calculated if ethereumData is used
  • sendFormActionsRipple does calculation locally, additional account.reserve check on recipient address


  • PrecomposedLevel are calculated for all possible FeeLevel at once.
  • if FeeLevel wasn't changed by the user and current PrecomposedLevel has error then tries to switch to a lower/custom possible FeeLevel
  • if PrecomposedLevel has error set this error in react-hook-form
  • if PrecomposedLevel has set-max set calculated amount in react-hook-form

Transaction signing process

Every networkType has own sendFormActions.signTransaction method. This process is async may be interrupted by the user (ReviewTransaction cancel, disconnect device etc.)