# Transaction Lifecycle
This document describes the lifecycle of a transaction from creation to committed state changes on the EVM.
# Pre-requisite Readings
Haqq needs to parse and handle transactions routed for both the EVM and for Cosmos SDK modules. We
attempt to achieve this by mimicking geth's (opens new window)
structure and treat it as a unique Cosmos SDK message type. An Ethereum transaction is a single
sdk.Msg (opens new window). All relevant Ethereum
transaction information is contained in this message. This includes the signature, gas, payload,
Being that Haqq implements the Tendermint ABCI application interface, as transactions are
consumed, they are passed through a series of handlers. Once such handler, the
responsible for performing preliminary message execution business logic such as fee payment,
signature verification, etc. This is particular to Cosmos SDK routed transactions. Ethereum routed
transactions will bypass this as the EVM handles the same business logic.
All EVM transactions are RLP encoded using a custom tx encoder.
The signature processing and verification in Ethereum is performed by the
Signer interface. The
protocol supports different signer types based on the chain configuration params and the block number.
Haqq supports all Ethereum
Signers up to the latest go-ethereum version (London, Berlin,
EIP155, Homestead and Frontier). The chain will generate the latest
Signer type depending on the