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Is it possible to send bitcoins with an attached message with the transaction? If yes how to do it?

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    have you tried to send a transaction with a message in bitcoin-qt? – V-X Jan 5 '14 at 19:35
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    yes. but I couldn't figure out how – Sathish Manohar Jan 5 '14 at 19:50
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    @V-X That creates a signed message, but the question is about whether you can attach that signed message to a transaction. – David Schwartz Jan 5 '14 at 20:37
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    I believe there are some chains that allow that. I'm not sure if it has been merged upstream to bitcoin or not. I know I've been discussing ways to do messaging within a coin blockchain (vs bitmessage). You could use a blockchain.info wallet and send a message over blockchain.info. – Joe White Jan 5 '14 at 21:20
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    Bitcoin transactions are not supposed to contain messages; only what is necessary for the world to validate your transaction. The rest is private information between you and the receiver, and just spam to the rest of the world. – Pieter Wuille Mar 12 '14 at 0:57
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The payment protocol (see BIP 70-72) will support attaching messages to transactions.

Note that these messages do not end up in the blockchain, which is the right way to do it, as they are private information between sender and receiver - no need to make the entire world replicate it.

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    where does these messages get stored and how are they being processed to be sent to the recipient? If its sent via email, who is sending the email and doesn't that mean the merchant have to have something in place to send these emails? – Patoshi パトシ Mar 4 '17 at 19:00
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    They're in the sender and the receiver wallet, and the message is communicated through whatever means is used to convey the payment request. A better response to this question these days is how Lightning payments also can have messages associated, even though there is not even a transaction on chain for the payment. – Pieter Wuille Apr 7 '18 at 14:38
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If you are just looking to encode a message into the URI, then look at BIP 20. If you want to actually associate the message in the block chain, then I would take a look at this stack overflow question.

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Technical details of how to do this are dicussed here. https://bitcoin.stackexchange.com/search?q=encode+message+in+the+block+chain The best way seems to be using the transaction output script.

Blockchain.info has this capabilities in it's wallets. Not sure what other wallets allow it.

protected by Community Sep 29 '17 at 12:10

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