Transaction Fee

[NwachukwuOfoma]

Why must there be a transaction fee to perform transaction fees and to the blockchain?

[zemse]

What if the transaction fee is not there?

If you had to send 10$ to someone:

• you could do that in single tx of $10
• or you could send two txs of $5 $5 each
• or you could send 10 txs of $1 each
• or you could send 100 txs of $0.1 each

When you send one tx, it consumes some network, storage, processing resources. If there wasn't any fee, one could potentially do thousands/millions of useless transactions and spam the network to use up all the resources, preventing genuine users from using them. Does that make sense?

[NwachukwuOfoma]

So there is a physical real word limitation to how much information the networks can process so to make sure only genuine work is done there is a gas fee?

[zemse]

Exactly there is a blockGasLimit, which on ethereum mainnet is currently 30 million computation units (called gas). One simple ether transfer costs 21000 gas. So you can see that in one ethereum block you can do no more than 1400 transactions. In practice, the transactions on ethereum do complex computation and cost more than 21000 and hence the number of transactions on ethereum per plock are around 100~300.

[zemse]

You may read some online blog posts for more understanding. Linking few here

https://education.district0x.io/general-topics/understanding-ethereum/what-is-gas/
https://legacy.ethgasstation.info/blog/eip-1559/