# Gas and Fees
Learn about the differences between
Fees the Injective Chain.
# Pre-requisite Readings
The concept of Gas represents the amount of computational effort required to execute specific operations on the state machine.
The Injective Chain utilizes the concept of gas to track the resource usage of operations during execution. Operations on the Cosmos SDK (which the Injective Protocol is built on) are represented as read or writes done to the chain's store.
A fee is calculated and charged to the user during a message execution. This fee is calculated from the sum of all gas consumed in a message execution:
Gas is used to make sure that operations do not require an excess amount of computational power to complete and as a way to deter bad-acting users from spamming the network.
# Cosmos SDK
In the Cosmos SDK, gas is tracked in the main
GasMeter and the
GasMeter: keeps track of the gas consumed during executions that lead to state transitions. It is reset on every transaction execution.
BlockGasMeter: keeps track of the gas consumed in a block and enforces that the gas does not go over a predefined limit. This limit is defined in the Tendermint consensus parameters and can be changed via governance parameter change proposals.
More information regarding gas in Cosmos SDK can be found here.
In Cosmos, there are types of operations that are not triggered by transactions that can also result in state transitions. Concrete examples are the
EndBlock operations and the
AnteHandler checks, which might also read and write to the store before running the state transition from a transaction.
These operations are defined by the Tendermint Core's Application Blockchain Interface (ABCI) and are defined by each Cosmos SDK module. As their name suggest, they are executed at the beginning and at the end of each block processing respectively (i.e pre and post transaction execution).
The Cosmos SDK
performs basic checks prior to transaction execution. These checks are usually signature
verification, transaction field validation, transaction fees, etc.
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