Fee Token Contract

Git Source

The Fee Token Contract enables builders to deposit ETH which allows them to participate in building Hotshot blocks. While the Fee Token Contract facilitates deposits, Hotshot itself manages and tracks the working balance of builder deposits. Initially, the Fee Token Contract only supports deposits. Withdrawals are planned to be enabled after the initial launch.

function deposit(address user) public payable {

The contract defines a minimum and maximum amount for deposits to avoid errors and prevent the fee table from being filled with dust.

uint256 public immutable MAX_DEPOSIT_AMOUNT = 1 ether;
uint256 public immutable MIN_DEPOSIT_AMOUNT = 0.001 ether;

NOTE: For the next launch, withdrawals will not be enabled and thus the MAX_DEPOSIT_AMOUNT aims to minimize how much ETH is locked by a builder.


Builders are specialized entities that compete against one another in bidding for blockspace in Espresso. Espresso aims to utilize the Proposer Builder Separation (PBS) mechanism to enhance the block building process by enabling the ability to outsource block building to third parties, i.e. builders.

Public Write Methods


Allows anyone to deposit an ETH balance for any user

the deposit amount is less than a specified threshold to prevent fat finger errors

function deposit(address user) public payable;

Fee Token Contract UML

Fee Token Contract Dependency Graph

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