# AnteHandlers

The `x/feemarket` module provides `AnteDecorator`s that are recursively chained together into a single [`Antehandler`](https://github.com/cosmos/cosmos-sdk/blob/v0.43.0-alpha1/docs/architecture/adr-010-modular-antehandler.md). These decorators perform basic validity checks on an Ethereum or Cosmos SDK transaction, such that it could be thrown out of the transaction Mempool.

Note that the `AnteHandler` is run for every transaction and called on both `CheckTx` and `DeliverTx`.

### Decorators <a href="#decorators" id="decorators"></a>

#### `MinGasPriceDecorator` <a href="#mingaspricedecorator" id="mingaspricedecorator"></a>

Rejects Cosmos SDK transactions with transaction fees lower than `MinGasPrice * GasLimit`.

#### `EthMinGasPriceDecorator` <a href="#ethmingaspricedecorator" id="ethmingaspricedecorator"></a>

Rejects EVM transactions with transactions fees lower than `MinGasPrice * GasLimit`. - For `LegacyTx` and `AccessListTx`, the `GasPrice * GasLimit` is used. - For EIP-1559 (*aka.* `DynamicFeeTx`), the `EffectivePrice * GasLimit` is used.

{% hint style="info" %}
**Note**: For dynamic transactions, if the `feemarket` formula results in a `BaseFee` that lowers `EffectivePrice < MinGasPrices`, the users must increase the `GasTipCap` (priority fee) until `EffectivePrice > MinGasPrices`. Transactions with `MinGasPrices * GasLimit < transaction fee < EffectiveFee` are rejected by the `feemarket` `AnteHandle`.
{% endhint %}

#### `EthGasConsumeDecorator` <a href="#ethgasconsumedecorator" id="ethgasconsumedecorator"></a>

Calculates the effective fees to deduct and the tx priority according to EIP-1559 spec, then deducts the fees and sets the tx priority in the response.

```go
effectivePrice = min(baseFee + tipFeeCap, gasFeeCap)
effectiveTipFee = effectivePrice - baseFee
priority = effectiveTipFee / DefaultPriorityReduction
```

When there are multiple messages in the transaction, choose the lowest priority in them.