Replace by Fee

[johnny508]

Lots of folks (myself included) have had tx's sit unconfirmed for days due to a very low miner fee.  Also unconfirmed parents then begin to appear if more ex's are sent from same unconfirmed tx's associated coins.

Is this the benefit of the RBF function?  If I realize i put a fee of .00001 etc, i can raise it to .0005 etc for example to push tx thru quicker without mucking around with external sites to try to re-broadcast, etc.

Is my high level understanding correct?  Or if RBF something totally different?

[U2]

The long and short of it is that if you send a transaction with a small fee and it's unconfirmed, you can send another transaction with a higher fee. If it's unconfirmed you're free to do this but once it's confirmed it's set in stone unless the block is orphaned.

Read more here.

[kolloh]

Yep, just remember that Replace by Fee is opt-in so you won't be able to do it unless the original transaction was marked as a RBF transaction.

[pooya87]

RBF is replace by fee, it works like this:
you make a transaction with X satoshi/byte as fee and mark it as opt-in RBF. in other words your transaction is telling anyone who sees it, this transaction is an opt-in RBF.

then because there were other transactions out there which were paying higher fees than your X s/b, yours didn't confirm.

so you create another transaction and bump the fees up to X+Y s/b and broadcast it.

- if you had regular tx without RBF and created a new tx with X+Y s/b fee, nodes would have rejected it because it is a double spend and they already had the other tx in their mempool.
- but with RBF if nodes have implemented this option, they don't see the second tx as a double spend they simply replace the old one with the new one.

and remember that an RBF transaction is not a double spend because the outputs are the same only the fee changes.