The API returns the following parameters depending on the blockchain protocol used:

• When using a UTXO chain, it returns the fee, feeRate, ERC20TokenFees, maxFeePerGasGwei, and maxPriorityFeePerGasGwei parameters.
• When using an EVM chain, it returns the coin,blockNumber,timestamp, baseFeePerGas,type parameters and the slow,market and aggressive objects, each including the priorityFeeMultiplier,maxPriorityFeePerGas and maxFeePerGas parameters.

EVM blockchains return gas fee rates as per slow, market and aggressive estimates. The estimation types are used when passing the feelevel parameter in the Create transaction requests API. If you are using a custom value for the feeLevel parameter:

• Refer to the maxPriorityFeePerGas and maxFeePerGas fields when the blockchain protocol type is EIP 1559 (ETH), and
• Refer to the maxFeePerGas field when the blockchain protocol type is BNB (legacy).