How to add link in subject of email (gmail)

Question

Is there a way to add link in subject of email? Following is the example of YouTube -

Here in my code I'm trying the following but still unsatisfactory result. The below code is sending the subject as it is with printing the whole anchor tag in the subject.

public function contact_us($data)
{
    $from = "from@example.com";
    $to = "to@example.com";
    $view = 'emails/contact_us';
    $subject = "Contact Us <a href='http://www.example.com'>Link</a>";
    $view_data = $data;

    $this->send($from,$to,$subject,$view,$view_data);
}

Answer 1

I'm glad you asked! This is an awesome new feature and standard Google is supporting, part of the Schema.org initiative.

Copying their example here which allows customers to review something directly from the email! This block would be copied directly into your mail template.

<script type="application/ld+json">
{
  "@context":               "http://schema.org",
  "@type":                  "Restaurant",
  "name":                   "Google Cafe",
  "action": {
    "@type":                "ReviewAction",
    "review": {
      "@type":              "Review",
      "reviewRating": {
        "@type":            "Rating",
        "bestRating":       "5",
        "worstRating":      "1"
      }
    },
    "handler": {
      "@type":              "HttpActionHandler",
      "url":                "{{ review_url }}",
      "encoding": {
        "url":              "http://schema.org/Encoding/UrlEncoded"
      },
      "method":             "http://schema.org/HttpRequestMethod/POST",
      "requiredProperty": {
        "@type":            "Property",
        "name":             "review.reviewRating.ratingValue"
      },
      "optionalProperty": {
        "@type":            "Property",
        "name":             "review.reviewBody"
      }
    }
  }
}
</script>

Documentation on how to activate these features can be found here: https://developers.google.com/gmail/actions/