Some bitcoin payment processors provides instant payment called offchain transaction without waiting any confirmation, such as coinbase.

I was just curious. At first, I thought they would actually wait for the sum of bitcoins to be deposited into the business's wallet.
But it took me a bit to realize that all they need was confirmation that the sum was on its way, rather then making the customer wait such a prolonged amount of time.

Thanks    although I would say that I already know a good amount about Bitcoin. I was just curious as to how the transaction process was "sped-up" for business.
I've already confirmed what I thought.

IMHO - and this is just technical analysis - a company accepting bitcoins should have at least one full node to see the transaction after it was broadcasted. The more nodes the easier it is to determine if the transaction has propagated throughout network or only to the companies node. If the transaction is well known within the network it is reasonable safe to assume that the majority of the miners know about the transaction and will confirm it within the next block as long as the fee is high enough. This can not prevent a carefully planned doublespend attack, but as I am told business owners take more risks when accepting cash as an employee might not be able to determine a fake bill. Should the transaction have no/low fee and/or its priority is low the goods/serivce/coffee etc. could be delayed until the transaction has 1 confirmation.



What? Care to elaborate? What does this have to do with exchanges? What "specific tech" to "outsmart" others?

I guess the only way here is to look at the blockchain. Can't think of other way. Perhaps ask the customer to bear a higher tx fee so that it gets picked up faster and then refund the customer for paying the extra fee. But that would certainly end up a hassle. Plus it doesn't sound practical.

and a higher than usual fee will not result in miners finding a block faster. Most of the time you pay a fee your TX will be in the next block. Sometimes when there are almost 4k TX waiting [1] for a confirmation you might have to wait 3-4 blocks.

[1] as seen a few hours ago (~1830 on this picture https://i.imgur.com/kvH4ODO.png )

Using Bitcoin to buy a latte at Starbucks is like using gold to buy groceries.  Retail spending is the wrong application for a store of wealth.

XCN has reimplemented the blockchain in such a way that safe zero-confirmation transactions are possible: