title: How to send firebase auth sms in php?
body: <p>I want to send auth messages to users using PHP but firebase performs this function on the client-side only (e.g. Javascript).
  In javascript, I was able to write the following code</p>
  <pre><code>var phoneNumber = 'xxxxxxxxxxxxxxxx';
  var appVerifier = window.recaptchaVerifier;
  firebase.auth().signInWithPhoneNumber(phoneNumber, appVerifier)
  .then(function(confirmationResult) {
  
      console.log(confirmationResult);
  
  }).catch(function(error) {
  
      console.log(error);
  
  });
  </code></pre>
  <p>This code works just fine and sends the verification code (OTP) to the user successfully. But my requirement is to perform this task using PHP. How can I do that? How can I include required firebase files and then how can I run this javascript (or similar) code in PHP?
  Is there any way like creating REST APIs or something similar.</p>