Bitcoin Forum

How can you avoid having to wait the 10-30 minutes it takes for a transaction to confirm when accepting bitcoin for POS transactions?

when you deal only with little money (1-100 USD maybe) you dont have to wait. buy your coffee and walk out. the transactions are immediately and you can see that in the blockchain.

there is only very little danger of a double spending and you just have to wait when you buy expensive stuff (to be sure there is no double spending).

As far as I know there is no way at the moment. Some people may be fine with seeing the unconfirmed payment just going through, but most will want at least 1 confirmation. Some people have suggested that this could be mitigated in the future by using 'trusted' addresses or payment gateways.

Edit: Litecoinguy is correct. With small transactions there's not really much risk involved.

Submit the signed transaction to the merchant.  Merchant sends the transaction to the largest mining pools, who acknowledge that it is a valid transaction, which gives the merchant a higher probability that funds won't be double-spent before being confirmed.  The purchase would have to be a limited amount to minimize a potential loss.

I don't believe this is correct. By definition you cannot see an unconfirmed transaction in the blockchain. What makes unconfirmed transactions generally safe (but see below) is that once a tx  has propagated across the network, any double spend of the same coins will be rejected. Since it only takes a few seconds for a tx to propagate, for all practical purposes bitcoin transactions are instant and except for extremely high value transactions (where special but expensive attacks might be mounted), there is no need to wait for confirmation.

But nb it is my understanding that although it is generally safe to accept unconfirmed payments, it is NOT safe to accept unconfirmed payments that include any unconfirmed inputs (because of tx malleability). However, this is a special case which is being addressed in the latest release of QT and does not affect the broad picture that unconfirmed transactions are generally safe as long as the tx inputs are themselves all confirmed.

It would be pretty hard to double spend with a cell phone, plus if you managed to double spend in a store with cameras, you would have cops knocking at your door and your megahashing power possibly seized.  ;D

Every in person transaction that I have done in a retail settings has been accepted with zero confirms. Brick and Mortar businesses that accept bitcoin are very trusting of bitcoiners in general, and most are small ticket items (food, coffee, etc), where zero confirms are adequate. 

Thanks guys.  I know the risk is extremely low in these instances.  Have a client who wants bitcoin POS integrated but doesnt quite understand how it all works.  Looking for the easiest way to explain to someone that is bitcoin illiterate that receiving multiple confirmations isnt really necessary.