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  • I use a text field. I have built additions to text fields for ACF.

    First I add a setting to all text fields

    add_action('acf/render_field_settings/type=text', 'validate_text_as_href_setting');
    function validate_text_as_href_setting($field) {
      // this addes a setting to text fields
      // setting it to true will require that the content of the fields
      // meets requirements to be used as a link href value
      $args = array(
        'label' => 'Validate as HREF',
        'instructions' => 'Requires a valid href attribute. This includes values starting with: http://, https://, ftp://, mailto:, tel:, sms: /, and #',
        'type' => 'true_false',
        'name' => 'validate_href',
        'ui' => 1,
        'class' => ''
      acf_render_field_setting($field, $args);

    The I have a validation filter for all text fields

    add_action('acf/validate_value/type=text', 'validate_text_as_href', 10, 4);
    function validate_text_as_href($valid, $value, $field, $input) {
      // if the setting created by validate_text_as_href_setting
      // is true than this filter will text input to ensure it can
      // be used in as a link href value
      // this allows links starting with
      // / (site root relative), http://, https://, ftp://, # (anchor), mailto:, tel:
      if (!$valid) {
        return $valid;
      if (isset($field['validate_href']) && $field['validate_href'] && !empty($value)) {
        if (!preg_match('%^(https?\://|ftp\://|/|#|mailto\:|sms\:|tel\:)%i', $value)) {
          $valid = 'Enter a Valid HREF Value';
      return $valid;

    I use another text field for the link text.

    then, of course there is the code to add to show the link

    <a href="<?php the_field('my_link_field"); ?>"><?php the_field('my_link_text_field'); ?></a>