Basic PHP Email Validation Example using PostCoder Web. Find out more at - http://developers.alliescomputing.com/postcoder-web-api/email-validation

email-validation.php

<?php
	// Check if POST request has been made
	if($_SERVER['REQUEST_METHOD'] === 'POST') {
	
		// Basic validation on the email field
		if(array_key_exists('email', $_POST) and !empty($_POST['email'])) {

			// Insert your PostCoder Web API Key here 
			// Sign up for free at www.alliescomputing.com/postcoder/sign-up
			$pcw_api_key = "YOUR-API-KEY-HERE";
	
			// URL we are calling with API key and url encoded email
			$pcw_validate_url = "http://ws.postcoder.com/pcw/". $pcw_api_key ."/email/" . rawurlencode($_POST['email']);
		
			// Get and JSON decode the response from the service
			$response = json_decode(file_get_contents($pcw_validate_url));
						
			// Was the response TRUE or FALSE, show the correct message
			if($response->valid === FALSE) {
			
				echo "<p><strong>" . $_POST['email'] . "</strong> - IS NOT a valid email address</p>";
			
			} else {
			
				echo "<p><strong>" . $_POST['email'] . "</strong> - IS a valid email address</p>";
			
			}
			
			// Certain domains only allow minimal validation, if so this warning will be present
			if(isset($response->warning)) {
			
				echo "<p>Warning: " . $response->warning . "</p>";
			
			}
	
		}
	
	}

	// Basic POST submit form HTML below

?>
<form action="email-validation.php" method="post">

	<fieldset>
		<label for="email">Email Address:</label>
		<input type="text" name="email" id="email">
	</fieldset>

	<input type="submit" value="Validate">

</form>