​
Purpose

This section outlines the overall fee structure of the protocol, how fees are applied and at what level the fees are applied. Each fee type has its own documentation associated to the specifics of that Fee type and are stored in the fee guide.

A Fee data contract is deployed at the same time as the token handler. All supporting fee data is stored in this contract and owned by the handler. Data contracts can be migrated to a new handler in the event of an upgrade so that fee data is not lost. Only the previous handler owner or app administrators can migrate the data contracts. Migrations to a new handler are completed through a two step migration process.

Fees are applied to accounts via general tags in the AppMananger. Each Fee applied via tags to an account can be additive (increase the fee amount owed) or subtractive (reduce the fee amount owed) and are expressed in basis points.

Protocol supported tokens will always assess all fees asigned to the account executing the current function. If a token has fees active and an account is tagged with applicable fees or a blank tag is used to assign a default fee, those fees are assessed on token transfers (additive). Token fees are assessed and taken from the token itself, not a collateralized token, when fees are active in the token handler.

​
Applies To:

  • ERC20
  • ERC721

​
Scope

​
Token Fees:

Token Fees work at the token level. Fees must be activated and configured for each token in the corresponding token handler. Token fees are assessed in the transfer function of the token.

​
Fees Evaluation

​
Token Evaluation:

The token determines if the handler has fees active. The token retrieves all applicable fees for the account transferring tokens (msg.sender). The token loops through each applicable fee and sends that amount from the transfer total to the feeCollectorAccount for that fee. The total amount of fees assesed is tracked within the transfer as fees, upon completion of the loop the amount of tokens minus the fees is transferred to the recipient of the transaction.

see an example UtilApplicationERC20 -> transfer

​
Evaluation Exceptions

  • There are no evaluation exceptions when fees are active. Fees are assessed in the token transfer function for token fees. No exceptions are made for the assessment of fees. If an address or account should not have fees assessed, there should not be a tag applied to it.

​
Transfer Fee

​
Purpose

The purpose of the Transfer Fee is to assess fees when protocol supported tokens are transferred. Application developers can utilize fees to influence their application’s economy through incentivizing behavior. Fees are assigned via tags applied to accounts through the App Manager. A blank tag may be used when adding a fee to apply to all accounts as a “default” fee. Token fees are added and activated through the token handler contract. Token transfer fees are assessed and taken from the token when fees are active in the token handler.

​
Application of Transfer Fee

Transfer fees are assessed in the transfer function of the token. The fees are additive. If a user has multiple applicable fees, the sum of all their fees will be assessed.

See Protocol Fee Structure

​
Dependencies

  • Tags: This rule relies on accounts having tags registered in their AppManager, and they should match at least one of the tags in the rule for it to have any effect.
GlossaryFee Guide