speeding up transactions?

[asianguy845]

Recently, I saw a website (I forgot where and what website) posted on a forum that said they could speed up your bitcoin transaction. It's not a scam because they didn't have anything for sale, and I didn't try it since I didn't have an ongoing transaction at the time. I'm just wondering, is this actually possible? And if so, would it cost money to do?

[jackg]

There are free services like viabtc's. It's direct from miners just doing something for people with small transactions that need fast confirms and they offer a members service too (which I think you get if you push mining power towards them). A few other sites have free and paid for services, the paid for ones are obviously a lot faster but they're normally more expensive than the minimum fee so you may as well rbf if you can.

Miners can pick what transactions they add to blocks so they'll just add yours instead of someone else's...

[HeRetiK]

Be careful though, there seems to be a handful of scams out there as well. Best check here on the forums if they are legit before making use of any of the paid services. ViaBTC as mentioned by jackg is one of the more trusted ones.

Keep in mind that transaction acceleration only means that the mining pool that is offering the acceleration service will add your transaction to the next block they mine. If that particular pool is unlucky you might still have to wait for a few blocks until your transaction gets its first confirmation.

[BitMaxz]

I'm just wondering, is this actually possible?

Yes,
It's possible but only mining operators or mining pools can speed up your transaction because they have option to choose what transaction they want to include on the block they mine.
Like the above said ViaBTC is the only one who offering it for free most of the mining pools are asking for a fee depends on the transaction fee of your transaction.

If there is someone offering to accelerate your transaction with payment better to stay away because they are most likely scam except for those who own a miner and mine on slush pool/other pools that offers accelerator only to those who mine on their pool.

Or you might be talking about this "[Guide] Broadcast Your RAW Transaction BTC & Alts coins" with BTC transaction accelerator?

[HCP]

Also... be careful trying to "find" the ViaBTC accelerator... Last time I checked, there are a number of scammy sites that seem to have purchased google ad words and/or similar domain names...

DO NOT use any of the following:

viabtc-accelerator.com
viabtc-com.com
viabtc-transaction-accelerator.com
www .btcaccelerator.net

As far as I can tell, they are all SCAMS

The correct url for the ViaBTC accelerator is: https://www.viabtc.com/tools/txaccelerator

And it looks like this:

[Lucius]

Using ViaBTC accelerator (free option) is not an easy task as it may seem, because in addition to having a limit of only 100 free transactions per hour, care should be taken that the fee is set to at least 0.0001BTC/KB. Also, before the submit button the captcha should be solved, and it can be a little tricky because it requires considerable precision (slide to validate captcha). Yet many times I used their free service and managed to push my transaction which got stuck due to low fee.

[joniboini]

I was browsing for this a few days ago and I find an accelerator that will speed up your tx for $30. Please avoid them even if it sounds convincing. Do RBF or use a 'trusted' accelerator as mentioned above. Never pay for anything like this imo. There's no guarantee your tx will get confirmed in the next block, assuming the accelerator is 'legit'.

[seoincorporation]

Recently, I saw a website (I forgot where and what website) posted on a forum that said they could speed up your bitcoin transaction. It's not a scam because they didn't have anything for sale, and I didn't try it since I didn't have an ongoing transaction at the time. I'm just wondering, is this actually possible? And if so, would it cost money to do?

Some scams are involved in this, so i would recommend to not use a service like that, if your fees are low then it will take more blocks to confirm, but it will confirm at some point. So, better be patient and take it as a lesson, next time use the right fees to have a confirmation in the next block.

[MrFreeDragon]

By default, miners should take the transactions with highest fees first, and with lower fees later.
Take your transaction instead of the one with higher fee is some kind of the violation. But it works, of course. And all the advises above are correct.

I just want to explain you small transaction fee trick which can be used by you:
Imagine you have the address A, and want to make a complex transaction sending to addresses B, C, D, E and the remainder to your exchange address F or the initial address A itself. You can make the following (your addresses marked by bod):
1) Make 1st transaction sending from A to B, C, D, E, F with the minimum fee (1sat/byte)
2) Make 2nd transaction from F to G with extremely high fee (100sat/byte)

The 1st transaction will not be mined as it is cheap, but the 2nd transaction will be immediately interesting for miners and the will confirm it as soon as possible. But, in in order to confirm 2nd transaction, the 1st transaction (because the 2nd transaction uses the output from the 1st transaction) also should be confirmed. So, you 1st transaction will be confirmed fast as well.

Slight variation: you can use the temporarily address X in the the 1st transaction, and send to X some small amount of satoshi (5-15k satoshi). And then with the 2nd transaction just "burn" the whole that balance to OP_RETURN - the whole balance (5-15k satoshi) will go to the transaction fees.
It is better to use segwit or bech32 address as X address because that type of addresses require less satoshi per byte compared with legacy addresses.

By this trick we just increase sat/byte in the 2nd transaction because our 2nd transaction is very simple compared to the 1st complex transaction with many outputs (and probably many inputs as well).

[HCP]

The 1st transaction will not be mined as it is cheap, but the 2nd transaction will be immediately interesting for miners and the will confirm it as soon as possible. But, in in order to confirm 2nd transaction, the 1st transaction (because the 2nd transaction uses the output from the 1st transaction) also should be confirmed. So, you 1st transaction will be confirmed fast as well.
...
By this trick we just increase sat/byte in the 2nd transaction because our 2nd transaction is very simple compared to the 1st complex transaction with many outputs (and probably many inputs as well).

What you're describing here is "Child Pays For Parent" aka CPFP.

However, the miners are generally smart enough to figure out what the "average" fee rate is that you are paying across the 2 transactions... and will only prioritise the two transactions if the average fee rate used across both transactions is big enough!

Thus, if the first transaction (using 1 sat/byte) is 400 bytes... and your second transaction (using 100 sat/byte) is 226 bytes... then your "effective" fee rate for both transactions is actually (600+22600 sats / 400 + 226 bytes) == 37 sats/byte.

So, if enough other transactions are still paying 40+ sats/byte, you might find that your small 100 sat/byte transaction is not that "interesting" after all

[MrFreeDragon]

-snip-
However, the miners are generally smart enough to figure out what the "average" fee rate is that you are paying across the 2 transactions... and will only prioritise the two transactions if the average fee rate used across both transactions is big enough!
-snip-

I am not sure that this "average transaction fee" works in practice. I tried several times the described CPFP method and it worked as a charm.

If 1st transaction 7000 bytes, so minimum fee for it 7000 satoshi (for legacy addresses, for segwit the min allowed fee is 30% less). The 2nd transaction has 192 bytes size, and paying for it 15000 satoshi means approx 78 sat/bye. If the blockchain average at that moment 25-30 sat/byte, transactions in my example are mined very fast (actually within the next 1-2 blocks). The 1nd transaction fee 2 times more than the average.

However considering the clever average approach, the actual average fee per byte is just (7000 + 15000)/(7000+192) = 3.05 sat/byte. The average fee is 10 times less than the average, so such transactions should be postponed by clever miners.

I guess not all miners look at the average transaction fee. In my case the "child pays for parent" worked even the average chain transaction fee was small like 2-4sat/byte compared with the network average.

[nc50lc]

@MrFreeDragon
What HCP explained should be the default behavior if the pool/miner uses Bitcoin Core v1.3.0 and above (source).

There must be something else that happened in your previous transactions like 'cleared mempool' due to faster blocks
or the "<1mb from tip" range is actually 3sat/B at that time.

[LoyceV]

I am not sure that this "average transaction fee" works in practice. I tried several times the described CPFP method and it worked as a charm.

If 1st transaction 7000 bytes, so minimum fee for it 7000 satoshi (for legacy addresses, for segwit the min allowed fee is 30% less). The 2nd transaction has 192 bytes size, and paying for it 15000 satoshi means approx 78 sat/bye. If the blockchain average at that moment 25-30 sat/byte, transactions in my example are mined very fast (actually within the next 1-2 blocks). The 1nd transaction fee 2 times more than the average.

However considering the clever average approach, the actual average fee per byte is just (7000 + 15000)/(7000+192) = 3.05 sat/byte. The average fee is 10 times less than the average, so such transactions should be postponed by clever miners.

My assumption until now what that HCP's theory is correct. It would be interesting to test your "trick", by sending a second transaction from a confirmed input with slightly higher fee than the average. If you're right, the CPFP transaction should confirm before the second transaction. If that's correct, (some) miners are dumb and this would be a really cool trick to reduce fees.

Instead of making a second transaction, you could also look at all transactions in the same block, and see if there is any transaction that has a lower fee than your average.[/quote]

There must be something else that happened in your previous transactions like 'cleared mempool' due to faster blocks
or the "<1mb from tip" range is actually 3sat/B at that time.

Johoe's Bitcoin Mempool Size Statistics shows the fee can drop quite a lot once a single block has been minded, so I wouldn't be surprised to see a 3 sat/byte transaction included even when your wallet says 30 sat/byte is needed. In my experience, many wallets are just bad at fee estimates.

In general, to reduce fees:

• Consolidate your small inputs when you're not in a hurry.
• Use native SegWit (Bech32; addresses starting with bc1q....
• Use coin control: manually select which inputs you're going to use. Don't use more inputs than needed. This reduces the transaction size and thus the fee.