How exactly is the block height defined in EOS?

Question

I wanna show users the confirmation height of their transactions. Which one is the way to go?

Latest block - transaction block

OR

Last irreversible block - transaction block ?

Answer 1

According to the whitepaper:

Transaction Confirmation

Typical DPOS blockchains have 100% block producer participation. A transaction can be considered confirmed with 99.9% certainty after an average of 0.25 seconds from time of broadcast.

In addition to DPOS, EOS.IO adds asynchronous Byzantine Fault Tolerance (aBFT) for faster achievement of irreversibility. The aBFT algorithm provides 100% confirmation of irreversibility within 1 second.

Therefore, unlike in other blockchains, I would say the message should be binary: your transaction is irreversible (behind an irreversible block) or your transaction is not yet irreversible but has X confirmations (Latest block - transaction block)