Is there an api that I can use to send messages with the blockchain?

[Btcvilla]

I would like to send messages with the Blockchain, is there an api to do this? I'm also trying to do it in c# if possible.

[NyeFe]

You can't send messages, when sending bitcoins to an address. However, if the users registered on your website, using c#, you can make an encrypted http or https call to the webserver, with an extra parameter for sending messages, images,..... Which can be viewed/shared if the receiver and sender have their block chain.info wallet on your website. Pretty simple

P.S.

If you could add a message, it would be available not only to the reciever, but to everyone who ever explores the blockchain and decodes the message. So I would stick to the first method.

[cr1776]

Take a look at this thread, it was just discussed a few days ago:

https://bitcointalk.org/index.php?topic=962540.0

[Btcvilla]

Take a look at this thread, it was just discussed a few days ago:

https://bitcointalk.org/index.php?topic=962540.0

Thanks.

[cr1776]

Take a look at this thread, it was just discussed a few days ago:

https://bitcointalk.org/index.php?topic=962540.0

Thanks.

Sure.  ;-)

Hopefully it helps!

[simonbtc]

You can send messages over Bitcoin with CoinSpark (an OP_RETURN based protocol).

http://www.coindesk.com/coinspark-blockchain-notarized-messaging/

Messages are not stored on the Bitcoin blockchain itself but are sent out-of-band via message delivery servers.  When you send a message with a bitcoin transaction, the blockchain only stores enough details for the recipient to retrieve the message and ensure it is valid.  CoinSpark runs some community servers but you can run your own server and modify it to meet your needs as the code is open-source.

Get started by downloading SparkBit, a lightweight SPV wallet based on MultiBit:
http://www.coinspark.org

Developers can find open-source libraries and docs here:
http://coinspark.org/developers/messages-introduction/