UPGRADING.md

Upgrading Your Chain to Use FeeMarket

Code Changes

To integrate your chain with x/feemarket, the following steps should be performed:

Add the Module to Your App

• The FeeMarketKeeper must be added to your application as seen here.
• A DenomResolver (if desired) must be set in your application as seen here.
• Ante and Post handlers must be configured and set with the application FeeMarketKeeper as seen here.

Determine Parameters

We provide sensible default parameters for running either the EIP-1559 or AIMD EIP-1559 feemarkets.

Note

The default parameters use the default Cosmos SDK bond denomination. The should be modified to your chain's fee denomination.

Changes for End-Users

With the addition of x/feemarket, there are some important changes that end-users must be aware of.

1. A non-zero fee is always required for all transactions.
   1. Pre-x/feemarket validators were able to set their MinGasPrice field locally, meaning it was possibly for some to have no required fees. This is no longer true as there is always a non-zero global fee for transactions.
2. Fees are no longer static.
   1. The gas price will change with market activity, so to ensure that transactions will be included, wallets, relayers, etc. will need to query x/feemarket for the current fee state. See the Querying Gas Price section below.
3. Fees must always be a single coin denomination.
   1. Example --fees skip is valid while --fees 10stake,10skip is invalid

Note

Fees are still paid using the fees field of a Cosmos SDK Transaction as they were before.

Querying Gas Price

Information on how to query and use dynamic gas prices can be found here.