That being said, it's basically a cut-and-paste example in php. Which language will you use for your project?
Just need help to understand
$callback_url = "https://site.com/IPN.php?user=2450";
If I don't declare any ?user=xx value will the following data still get sent back to my callback URL?
The following details will be sent to your callback URL upon receiving payments, Payment notification are sent every minute up until the transaction gets 3 confirmations.
$address = $_POST["address"];
$amount = $_POST["amount"];
$confirmations = $_POST["confirmations"];
$hash = $_POST["hash"];
$auth_hmac = $_POST["auth_hmac"];
Thank you
Sure. address, amount, confirmations, hash and auth_hmac will be posted to your callback url.
Legend! Thank you for clarification. I am building a website to sell HTML templates and wish to accept bitcoin payments.