That's Why We Prefer to Use BitAccelerate Instead of RBF and CPFP

As a financial company, we make hundreds of Bitcoin transactions every day. We use https://bitref.com/fees/ to select the optimal fee rate for every transaction. However, sometimes the Bitcoin network becomes congested after a transaction has been broadcast, causing it to remain stuck in the mempool for hours or even days.

The most common solution in this situation is to use RBF (Replace-By-Fee) to replace the stuck transaction with a new one that pays a higher fee. This has become the standard approach, and most Bitcoin wallets support RBF nowadays. Some Bitcoin nodes even support Full RBF, allowing transactions that were not originally marked as replaceable to be replaced.

However, this technique has one major disadvantage: the transaction ID (TxID) changes. This can create serious problems. Some payment systems do not expect the TxID to change after they detect a transaction in the mempool. Instead, they simply wait for that transaction to be confirmed. If the transaction is replaced, the original TxID is never confirmed because it no longer exists.

As a result, the payment may fail and, even worse, the funds we sent may never be credited by the recipient. Recovering large payments in such situations can be extremely difficult. That's why we prefer to use a transaction acceleration service instead of RBF. We use BitAccelerate https://bitaccelerate.com/ because it currently offers the best pricing. The TxID remains unchanged, and BitAccelerate has proven to be reliable for us.

Even their free transaction acceleration service works for most transactions. For larger or more important payments, we use their premium service because the pricing is very reasonable. The premium service prioritizes the transaction across more than 10 Bitcoin mining pools. When one of those pools finds a block, the accelerated transaction has a much higher chance of being included and confirmed.

Another important recommendation is to always validate the recipient's Bitcoin address before sending funds. We use https://bitref.com/address-validator/ for this purpose. It is surprisingly common for customers or partners to provide an incorrect Bitcoin address. Sending funds to an invalid or unintended address can result in permanent loss, as Bitcoin transactions cannot be reversed.

In some cases, it is also possible to increase a transaction's effective fee rate using CPFP (Child Pays For Parent). When you send a Bitcoin transaction, there is often a change output that returns the remaining funds to one of your own Bitcoin addresses. This output can be spent immediately, even before the original transaction is confirmed, and most wallets support spending unconfirmed outputs.

By assigning a very high fee to this second (child) transaction, you increase the average fee rate of the entire transaction package. As a result, miners are more likely to include both transactions in the same block. We use BitAccelerate's free CPFP calculator: https://bitaccelerate.com/cpfp-calculator/. However, this method requires some technical knowledge and only works if the original transaction contains a change output.

To monitor the status of our transactions, we use the BitRef Bitcoin Explorer: https://bitref.com/ . BitRef includes one of the most advanced Bitcoin transaction analyzers available. It extracts all transaction ancestors and descendants and calculates the effective fee rate of the entire transaction package. This is the fee rate miners consider when deciding whether to include a transaction in the next block.

Conclusion

These are the tools we use every day for our Bitcoin operations. In conclusion, be cautious when using RBF. Many services cannot reliably track transaction replacements, and implementing such support is technically challenging. Whenever possible, we recommend using a transaction acceleration service or, if the transaction has a change output, CPFP instead.