How to specify default `Max Priority Fee` for custom network

[shunjizhan]

Hi, I searched issues and stackexchange but couldn't find a solution, any help would be appreciated!

Describe the issue

when sending token with a custom network that has custom RPC methods implementation , I can see that Metamask fetches:

• max fee by eth_gasPrice
• gas limit by eth_estimateGas.
• max priority fee: ??

However, I was not able to figure out how metamask determines the default Max Priority Fee, which is currently the same as gas limit.

Expected behavior

I hope to be able to set a default Max Priority Fee value (such as 1.5), either by hardcoding it somewhere, or deriving it from any RPC calls (I can customize any RPC calls for this network).

Screenshots

from the screenshot we can see that after clicking send and Next, on the gas settings page, max priority fee is the same as max fee

Browser details

• OS: OS X
• Browser: Chrome
• MetaMask Version: 10.8.1

[shunjizhan]

If I am correct, for ETH mainnet metamask will make a request to https://gas-api.metaswap.codefi.network/networks/1/suggestedGasFees, and use the suggestedMaxPriorityFeePerGas for default Max Priority Fee, is there anything similar happen for custom networks?

[jpuri]

Hey @shunjizhan : you are right for mainnet metamask utilises suggestedMaxPriorityFeePerGas as default for Max Priority Fee.

If suggestedMaxPriorityFeePerGas is not provided Max Priority Fee also defaults to eth_gasPrice.

[shunjizhan]

Thanks @jpuri 😀

How about for other custom networks? Since my chainid is 595 I did see this call once:

https://gas-api.metaswap.codefi.network/networks/595/suggestedGasFees

However nothing was returned (as expected, since it is currently a local testnet).

Any idea how I could provide a default Max Priority Fee for end users, such as 1?

[shunjizhan]

is https://gas-api.metaswap.codefi.network/networks/CHAIN_ID/suggestedGasFees the only source of truth for the default Max Priority Fee? And does it indicates that for custom networks, default Max Priority Fee is always the same as eth_gasPrice (unless user manually edit it)?

[HeyFloM]

Heya @shunjizhan , have you found the solution? Having the same issue here! Thanks!

[shunjizhan]

Hi @HeyFloM, we switched back to legacy gasPrice/gaslimit instead of using eip-1559 as the workaround