How can one troubleshoot and debug issues with Paypal IPN integration in PHP scripts?

To troubleshoot and debug issues with Paypal IPN integration in PHP scripts, you can start by checking the IPN history in your Paypal account to see if there are any errors reported. Make sure your IPN listener script is correctly configured to receive and process IPN messages from Paypal. Additionally, log any incoming IPN messages to a file or database to track the data being sent by Paypal and verify that your script is handling it correctly.

// Sample PHP code snippet for logging incoming IPN messages
$raw_post_data = file_get_contents('php://input');
$decoded_post_data = urldecode($raw_post_data);

// Log the IPN message to a file
$log_file = 'ipn_logs.txt';
file_put_contents($log_file, date('Y-m-d H:i:s') . ' - ' . $decoded_post_data . PHP_EOL, FILE_APPEND);