What are Coin Cleanup Fee (defrag fee) and Network Fee?


I am wondering what cleanup fee and network fee are about.

About cleanup fee:

All I could find about it is that it only occurs when a transaction requires 16 inputs and outputs, that it happens only when there is no other way to complete a transaction and that it’s sometimes called defrag fee.

What is this ‘combining of coins’?
What are ‘inputs and outputs’?

And what is network fee?

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A cryptocurrency is a collection of ‘messages’. Each message says something like “person X owns amount A”. A transaction by person X spends some of the messages owned by X (i.e. makes it so X cannot spend them again), and makes new messages sending amounts to new people. An ‘output’ is just a message that is put out by a tx, and an ‘input’ is just an old message being spent (i.e. an old output).

Your balance is the sum of amounts in the unspent outputs that you own (i.e. have the right to spend).

  • If you have a lot of unspent outputs, then you can ‘defragment’ your wallet by constructing transactions that combine them into fewer outputs containing the same total amount. I am guessing the cleanup/defrag fee is the cost in network fees to ‘defragment’ your wallet.
  • A network fee is the amount you must send to the MC foundation if you want to make a transaction. This exists to prevent transaction spam.
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