Send messages with payment

[Guardian3Healer]

https://bitcoin.stackexchange.com/questions/19893/how-to-send-bitcoin-with-a-message-attached

"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."

Can we get this in the NAVPay wallet? It will significantly help merchants with payments in environments that aren't naturally secure.

"Send 15 NAV with the message 'hoodie' to (NAV address or QR code) with your shipping address and you'll get 15% off!"

Something like that. It reminds of automatic texting applications that used to be popular in....like 2005.

I'm told NAV forked off of bitcoin version 0.13 which was released in 2016 and this capability has been available with bitcoin since at least 2014. All I'm asking for is that it be park of the normal NAVPay functions.

[Guardian3Healer]

A comment made by Prole on the NAV discord:
So effectively, the merchant specifies a URL that NavPay would query over TCP like
https://mystore.com/validate-discount-code?discountCode=NAVCOIN_RULES
and all NavPay would do is send the query and the merchant has to handle the rest
and then once it responds, navpay can make the payment
through the normal sending api to the navpay back end
the merchant site would need to respond with data we know something to do with like reduce the payment amount by X %
and we update the send amount
and make the payment

[aguycalled]

Related to this and Payment Protocol:
I'd consider also porting BTCPay (BitPay alternative :-) to Nav.
https://github.com/btcpayserver