Max Priority Fee Per Gas

Overview

The maxPriorityFeePerGas field limits the priority component of an EIP-1559 transaction. Validators or block proposers generally receive the effective priority fee, while the base fee is handled according to the network’s protocol rules. On Ethereum, the base fee is burned.

The effective priority fee is bounded by two values: the sender’s max priority fee and the difference between maxFeePerGas and the current base fee. This means a transaction that advertises a large priority cap may pay a smaller tip if its total fee cap is tight.

Wallets estimate an appropriate priority cap from recent inclusion conditions and user urgency. The value should be displayed separately from base fee and estimated total cost. Increasing only the priority cap may not help if maxFeePerGas remains below the base fee required for inclusion.

Payment infrastructure should retain both fee-cap fields and the receipt’s effective gas price. It should also track replacements that reuse the same nonce with revised fee settings. This evidence helps support teams distinguish a delayed transaction, an underpriced replacement, and a transaction that executed with a lower effective tip than expected.

Networks and transaction types can use different fee semantics. Integrations should confirm that the field is supported by the active client and avoid applying Ethereum-specific assumptions to legacy transactions or unrelated fee markets.

For example, a wallet may raise maxPriorityFeePerGas during congestion to improve inclusion probability, but the effective proposer tip can still be lower when maxFeePerGas leaves insufficient room above the base fee. Integrations should store both caps and the confirmed effective gas price. This distinction prevents a pre-submission tip setting from being reported as the amount ultimately paid.