.. index:: ! fees

.. _fees:

##########
Flat fee
##########


When a swap is traded on the DEX, a flat fee will is charged by the DEX that is fully covered by the swap taker.

Per default the flat fee is 0.001 Ether per trade on Ethereum and [TBD] Matic per trade on Polygon.


.. _fee_discount:

Fee discount
============

A swap taker can reduce or even bypass the fee entirely by owning NFT.org tokens ($NFT).
The contract maintains a fee bypass low threshold `felo` and a fee bypass high threshold `fehi`.

If the taker owns less than `felo` $NFT tokens, the full flat fee will be charged.

If the taker owns equal to `felo` $NFT tokens, then they receive a 10% discount and have to pay only 90% of the flat fee.

If the taker owns more than `felo` and less than `fehi` $NFT tokens, then the discount scales linearly from 10% to 100%, respectively.

The following list shows examples for fee discounts based on the taker's $NFT token balance:

* full flat fee below a 10,000 $NFT token balance,
* 90% of flat fee at a 10,000 $NFT token balance,
* 80% of flat fee at a 20,000 $NFT token balance,
* 70% of flat fee at a 30,000 $NFT token balance,
* 60% of flat fee at a 40,000 $NFT token balance,
* 50% of flat fee at a 50,000 $NFT token balance,
* 40% of flat fee at a 60,000 $NFT token balance,
* 30% of flat fee at a 70,000 $NFT token balance,
* 20% of flat fee at a 80,000 $NFT token balance,
* 10% of flat fee at a 90,000 $NFT token balance,
* no fee at a 100,000 or higher $NFT token balance.

The `felo` and `fehi` thresholds can be changed by the multisig account.

If the taker sends more Ether than was required as a fee, then the excess amount will be returned to the taker by
booking a refund to their account on the DEX. The refund can be withdrawn using the `pull` function in the contract.

A user can inspect the available withdrawal balance using the contract's `pend` function.


Paying the fee
==============

The swap is paid by the swap taker, and the amount of Wei of Ether to be paid can be queried using the `fees` function in the contract.
This function will inspect the balance of NFT.org tokens of the taker account and applies the discount accordingly.