<p>If you want to detect a double spend, you need to listen to all transactions broadcasted to the network, and write some code to detect if the address that sent you Bitcoins also sends a transaction to another address (until 1+ confirmations).</p>

<p>To answer your other question, Bitpay cannot guarantee the transactions not to be double spent. In an effort to promote usage of Bitcoin as a payment solution, they take on the risk of a potential double spend, and if one happens, they eat the balance (no risk to the merchant). This is a vanishingly small occurrence in practice, so any fees (or venture capital) paid to them more than cover that possibility.</p>

CC BY-SA 3.0
2015-08-15T07:26:24.320Z
2015-08-15T07:26:24.320Z
LivingInformation
<p>By Bitpay to pay only take 10 seconds to complete.</p>

<p>How do they do it?</p>

<doublespend>
How do I detect a double-spend in real-time, like Bitpay?
J.Lee
# How do I detect a double-spend in real-time, like Bitpay?

(Asked by: username_0 on 2015-08-15)

By Bitpay to pay only take 10 seconds to complete.

How do they do it?

**Tags:** doublespend


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## 1 answers

### Answer by username_1 on 2015-08-15. Score: 0 | Accepted answer

If you want to detect a double spend, you need to listen to all transactions broadcasted to the network, and write some code to detect if the address that sent you Bitcoins also sends a transaction to another address (until 1+ confirmations).

To answer your other question, Bitpay cannot guarantee the transactions not to be double spent. In an effort to promote usage of Bitcoin as a payment solution, they take on the risk of a potential double spend, and if one happens, they eat the balance (no risk to the merchant). This is a vanishingly small occurrence in practice, so any fees (or venture capital) paid to them more than cover that possibility.


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