How accurate is the fee estimation in Electrum?

[HCP]

But the good news is, the site I sent it to credited my account, even though the transaction came in very late. So, everything went well in the end.

Generally, most of the payment processors, they only care that a valid transaction was broadcast to the network within the timeframe that they show the invoice as being "valid"... They will generally just not process your order or credit your account until that transaction is actually confirmed.

Any service that issues an invoice for say "30 minutes" and expects that a user can guarantee confirmation in that time frame (regardless of fee paid) is asking for trouble. As you saw, there can indeed be time periods where a block is not found for over an hour!

Sometimes, miners are just "unlucky"

[Melloiga]

not necessarily. you can always pay the minimum amount for a high priority transaction but mark it as RBF and if it didn't get confirmed in the next block and if you made sure that the mempool had indeed grown (eg. you can do it on https://jochen-hoenicke.de/queue/#0,24h) then you can simply bump its fee before the next block is found to the new minimum for high priority.

keep in mind that each time you bump your fee your transaction ID changes and although majority of services that i have seen have no issue with RBF and those that had bugs have fixed it already you may want to know what kind of service you are using in case your payment is to such services for a purchase for instance, otherwise deposits in your accounts like on an exchange have no issue.

Yes, you're right and I do use RBF but I am not sure if the company I sent my funds to would accept the deposit if the transaction ID changes.

I'll ask them before about this when I deposit the next time. Also, the last time it happened. The service I sent the funds to asks you to enter the transaction ID in the field to show that you have made the payment.

And which is why I had to do CPFP to make that transaction confirmed when it didn't confirm after 10 hours because I couldn't change the tx id.

The services who don't accept the BTC directly are usually not sure what went wrong. I deposited BTC at one such service and even after 6 confirmations, my money wasn't credited in my account.

When I asked their support. They told me that the transaction needs to get confirmed. And I told them that it already has 6 confirmations and it is unreturnable at this point. And they answered that it is not confirmed at their end.  

I told them that if a transaction is confirmed at one end, it is confirmed everywhere. And they told me to wait an hour.

But the good news is, the site I sent it to credited my account, even though the transaction came in very late. So, everything went well in the end.

Generally, most of the payment processors, they only care that a valid transaction was broadcast to the network within the timeframe that they show the invoice as being "valid"... They will generally just not process your order or credit your account until that transaction is actually confirmed.

Any service that issues an invoice for say "30 minutes" and expects that a user can guarantee confirmation in that time frame (regardless of fee paid) is asking for trouble. As you saw, there can indeed be time periods where a block is not found for over an hour!

Sometimes, miners are just "unlucky"

I think what they're looking for is for the first fast confirmation, so they can credit the company whose using their services because they accept the payment in fiat and payment processors have to pay them the exact amount, even if the bitcoin price drops in the meantime. Which is why they don't accept multiple payments to the same address and/or delay.

But yes, it is not possible to know when your tx might get accepted, even if you pay the proper fee. But it is scary when they tell you that time has passed and your tx might get lost or returned. How would it get lost, I can never understand?


Btw guys, a new user in India forum has asked some advice on how to upgrade his Electrum wallet. Although 2 users have already given him good advice. If you guys have anything to share on the matter that might help, pls do so. Here's the link to the thread: https://bitcointalk.org/index.php?topic=5277692.0

[pooya87]

I'll ask them before about this when I deposit the next time. Also, the last time it happened. The service I sent the funds to asks you to enter the transaction ID in the field to show that you have made the payment.

sadly there still are some bad services that follow the transaction ID instead of only watching the fresh and unique address they've generated for the customer, which should be the case everywhere. it is not that hard to change either which makes you wonder why they are not doing it after all this time!

[HCP]

Wait what? They track an individual's payments based purely on TransactionID?

That seems like a recipe for disaster!!?! And also prevents users from using RBF etc

[hosseinimr93]

Wait what? They track an individual's payments based purely on TransactionID?

It's not the first time I've heard of such an issue.
They do track the address. But once a payment is made, they no longer track new transactions and wait for the first transaction to be confirmed. If the first transaction is removed, they consider the payment as failed.

Look at following thread. There was a same issue with Changelly. (The OP's problem was solved after contacting their support, off course.)

Please help with coins missing in transaction.

[pooya87]

That's the problem with most customer support where the employee doesn't have technical knowledge and only know how to solve common problem.

not just the customer support employee but the owners sometimes are just as bad. you'd be surprised to see how many of these companies that keep showing up like mushrooms have no idea what bitcoin even is. they pay minimum amount to a newbie developer to set things up for them and that's about as far as their efforts go!

[khaled0111]

Wait what? They track an individual's payments based purely on TransactionID?

That seems like a recipe for disaster!!?! And also prevents users from using RBF etc

Many of the services I used do this and some of them are long-established companies.  What I noticed is that those services either generate a new unique address for each new deposit or accept 0 confirmation transactions. I don't remember facing this problem when the deposit address is permanent.
In fact it makes sense if they have tons of addresses to monitor and they consolidate their inputs regularly.

I'm not sure how that company survive when malleability attack happened few years ago

I don't think it's in the customer's interest to conduct a malleability attack when using a service which accepts only the first seen transaction ID as valid.

[ranochigo]

Many of the services I used do this and some of them are long-established companies.  What I noticed is that those services either generate a new unique address for each new deposit or accept 0 confirmation transactions. I don't remember facing this problem when the deposit address is permanent.
In fact it makes sense if they have tons of addresses to monitor and they consolidate their inputs regularly.

Monitoring deposits based on the TXID is not the most efficient way about doing it. It would just cause unnecessary delay for the user and it would be a headache for them if the user decides to RBF due to low fees and whatnot.

I don't think it's in the customer's interest to conduct a malleability attack when using a service which accepts only the first seen transaction ID as valid.

It would be annoying for the company to handle hundreds of support messages regarding uncredited deposits due to the malleability issue.

[pooya87]

Monitoring deposits based on the TXID is not the most efficient way about doing it. It would just cause unnecessary delay for the user and it would be a headache for them if the user decides to RBF due to low fees and whatnot.
It would be annoying for the company to handle hundreds of support messages regarding uncredited deposits due to the malleability issue.

it is actually the laziest thing to do and considering the fact that many newcomers don't even know what RBF is i don't suppose these bad services get that many support tickets not to mention that they don't have that many users to begin with.
that may be the main reason why they haven't fixed their broken system.

[khaled0111]

Looks like you forget about malleability attack performed by someone which attack every single transaction on mempool.

See https://bitcoinmagazine.com/articles/the-who-what-why-and-how-of-the-ongoing-transaction-malleability-attack-1444253640

Thank you ETFbitcoin for the link, I read the full article and it only proves my point so I guess you misunderstood my previous reply.
What I was trying to say is that a customer will gain nothing by performing a malleability attack because, in our case, he is making a deposit. All it can cause is some nuisance to the customer service.
The attack can cause monetary loss in case we were talking about withdrawal transaction IDs. In such case if the service monitors only the txids then the attacker can claim he didn't receive his money and asks for a refund (it can be more dangerous if the refund process was automated).
I hope you got my point.

However, I agree with all the comments above. This is the worst approach when it comes to monitoring transactions.