Deposit and withdrawal fees
For internal operations, Orderbook uses Erc20 tokens to represent BTC, ETH and USD deposits.
When a user deposits Bitcoin or Ether, Orderbook initiates conversion of these coins into Erc20 tokens. This takes up two transactions. One to convert the tokens, and another for sending them to the user’s smart contract.
These transactions require a certain amount of fees (gas) to appear in the blockchain. That is what our deposit fees are spent on.
The same order of actions is relevant when conducting withdrawals.
More on Orderbook's architecture here.
Trading fees
Users create exchanges through Sell and Buy orders. Sell and Buy orders are matched when a Taker proposes a bid that is bigger or equal to a Maker’s ask.
Placing an order to be matched by some future person makes you the Maker. Matching someone's order makes you the Taker in that exchange. Order matching fees are covered entirely by Takers.
The Taker fee is a maximum between the fixed fee and the percentage fee (0.2%) from the amount traded. If the traded amount is less than fixed fee, however, the percentage fee is taken.