Reading: DeFi Awaits “Rude Awakening” as Bitcoin Rallies: Ex Goldman Partner


Child-Pays-For-Parent: Bitcoin Transactions Now Confirmed in Seconds


William Suberg | Dec 02, 2016 | 09:00

Bitcoinist transactions News

Child-Pays-For-Parent: Bitcoin Transactions Now Confirmed in Seconds


William Suberg | Dec 02, 2016 | 09:00


The torment of waiting hours for a Bitcoin transactions to confirm is officially over, thanks to a little-known trick called ‘child-pays-for-parent’ (CPFP).


 Transactions in Seconds from Most Wallets

A Reddit post by user super3 Friday states that if a transaction is sitting idle due to a low (or ‘standard’) fee, a CPFP transaction may be created to speed it up – drastically.


An unnamed developer reportedly confirmed the validity of the trick, which can be used with a variety of popular wallets.

I learned from one of the developers that works with me that you can use child-pays-for-parent transaction to move things along,” super3 wrote.

Using CPFP differs depending on the functionality of a user’s wallet. In principle, when the first transaction is idle, a second (CPFP) is created which spends the coins from the first (as yet unconfirmed) transaction.

This second transaction must include a significantly higher fee, so that it is confirmed much more quickly. However, the first transaction will be confirmed along with it.

“Once I sent that 2nd transaction it was confirmed 5 seconds later,” super3 reported.

Another user followed with a demonstration of how CPFP would work from a Copay wallet. This has an option to spend coins from an unconfirmed transaction, which are then used in the CPFP transaction to send funds back to oneself.

No Chance Of Double Spend

The procedure works due to the CPFP transaction being dependent on the first. As is highlighted in the Reddit thread, miners will see that both transactions need to be confirmed, and will collect both fees.

Once this is done, the change left which returns to the wallet it came from can be spent, thus avoiding any actual double spending taking place.


The discussion comes amid a recent spate of long delays confirming Bitcoin blockchain transactions. While it may provide temporary relief, however, concerns are being raised that CPFP could ultimately make very high fees the norm in order for transactions to be confirmed in seconds or minutes rather than hours.

Meanwhile, Bitcoin wallet providers and others have sought to find workarounds for customers this year. BitGo, with the launch of its BitGo Instant product, facilitated zero-confirmation transactions which were ‘approved’ immediately.

Using multi-signature technology, the wallet provider said at the January launch it would even cover the cost of any double spend transactions successfully executed using its zero-confirmation solution.

Have you tried child-pays-for-parent? What do you think about the effect on fees in future? Let us know in the comments section below!

Images courtesy of shutterstock

BitStarz Player Lands $2,459,124 Record Win! Could you be next big winner?

Show comments