How to Validate Payment Gateway Settings Fields

It seems like my complete payment gateway tutorial is not that complete after all. I didn’t mention there how you can validate payment gateway admin options.

For example let’s assume that we have to validate a USDT address of a TRON network. Here is how it should work:

how to validate WooCommerce payment method settings

Let’s assume that we’ve already added a field for a USDT address inside init_form_fields() method. Just like that:

public function init_form_fields(){

	$this->form_fields = array(
		'trc20_address' => array(
			'title'  => 'USDT address',
			'type'   => 'text',

There are actually two ways how we can validate this custom option field:

  1. We can add process_admin_options() method to our payment gateway class. Inside this method we can obtain the $_POST data with $this->get_post_data() method and then validate its particular array elements.
  2. Or simply use validate_{NAME}_field() method. I prefer this solution because it looks much cleaner in the code.
public function validate_trc20_address_field( $key, $value ) {

	if ( ! preg_match( '/^T[A-Za-z1-9]{33}$/', $value ) ) {
		WC_Admin_Settings::add_error( 'The wallet address doesn\'t look like a correct one.' );
		$value = ''; // empty it because it is not correct

	return $value;

I used a regular expression T[A-Za-z1-9]{33} in order to validate the USDT address.

Misha Rudrastyh

Misha Rudrastyh

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