I have had a 1 sat/vbyte transaction that has been stuck in the mempool for quite a while. Even with current low fees, it's been stuck for weeks.
I had to wait a few hours before I could do the replace-by-fee (RBF) because Bitcoin Core I used for that transaction wasn't synced yet with the blockchain and I had no funds left to increase the fee at that moment. I couldn't do Child Pays For Parent (CPFP) as I do not have access to the private key of the receiving address.
So, naively, I started looking into Bitcoin accelerators (mempool.space, viaBTC, Antpool, F2Pool, etc). All were charging fees ranging between 30,000 to 60,000k sats. viaBTC has a limited number of free acceleration per hour, but with my 1sat/vByte, I did not qualify. Some also asked for an email address to first make an account with them.
I also used https://bitaccelerate.com/ to rebroadcast my transaction to all the nodes, but as the fee was too low, it didn't make a difference. As recommended in #262460
I thus decided against the accelerators, waited patiently for a few hours, and managed to use RBF for less than 1500 sats. And it's really not that difficult. E.g. in Bitcoin Core, it's a few clicks using the GUI.
So my question to get back to my title ("unless you really have to"): Is there any reason to use accelerators over RBF/CPFP other than (arguably) the tools' user-friendliness?
I think some good use cases were talked about on Citadel Dispatch 135 with the mempool team.
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That's a long podcast :)
Luckily, timestaps below were helpful. About this point, seems like 00:44:44 is what you refer to. Quickly listened to it, and this seems to be the good use cases the mempool team highlights:
  • good way to monetize mempool.space, after the early days where they could get lots of grants.
  • convenience, just need to scan a LN invoice to accelerate your transaction to the front of the mempool.
  • you can use it if your wallet does not support RBF.
  • you can use it for some multisigs where RBF is not available
  • centralized approach is more efficient
  • "if not us, than who?"; "nefarious actors might also want to do it" (seems like same argument amboss used to justify they publish LN channel liquidity details thanks to insights they have thanks to their platform, even if it goes against the spirit of LN privacy)
Other than that, it's a lot of unstructured chatting, so I maybe missed something.
But all in all, seems like there is a need, especially for less technical users. And it makes sense they want to monetize their platform one way or another.
I probably won't have a need for it, but who knows.
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Nice! That’s what I was referring to. It does seem like it’s mostly geared towards less technical users.
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You can use CoinBin or CoinBin Clones to do this. And there is nothing wrong with waiting, miners will pick it up since there is no such thing as Zero mining fee. Accelerators should be thought of as a scam. Transactions will get stuck but when you are use to looking at the mempool and you know the whole cycle of Bitcoin transaction from creating through verifying through signing through Broadcasting. You are good to go.
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Didn't know about Coinbin. Thanks. So this would have allowed me to do the RBF without waiting for Bitcoin Core (from where I had initially done the transaction) to sync? Will look into it for next time.
We agree on the fact that the pricing of accelerators seems scammy. But if they do, it means there are people willing to pay. So why not :)
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