Calculating the transaction fee in BTC, BCH, LTC, Dash and Doge is not an easy task, all want to spend as less as possible for fee and in the same time to get their transaction mined as soon as possible.
We have an endpoint which is giving you the minimum, average and maximum paid fee. It's based on the last 70 blocks. This information is useful but it's not enough as transaction fee depends mainly on the size of the transaction, this size is in bytes. The more bytes is your transaction the more fee should be sent.
That's why we have created a new endpoint, this new endpoint will give you exactly how many bytes is your transaction, based on it and based on the previous endpoint you can calculate the needed minimum, average and maximum fee and decide which one you want to use.