How to remove captcha verification from Firebase phone auth using javascript?

Go to Firebase console -->to your project-->project overview settings-->project settings --> App check -->overview (Register your app for SafetyNet).

Then your app will stop redirecting to web for captcha verification

 firebase.initializeApp(firebaseConfig);
  // Create a Recaptcha verifier instance globally
  // Calls submitPhoneNumberAuth() when the captcha is verified
  window.recaptchaVerifier = new firebase.auth.RecaptchaVerifier(
    "recaptcha-container",
    {
      size: "invisible",
      callback: function(response) {
        submitPhoneNumberAuth();
      }
    }
  );

I had the same problem while integrating iOS SDK.

If google has same architecture and classes of the firebase SDK across languages, this solution might work for you.

Auth.auth().settings?.isAppVerificationDisabledForTesting = true

method 1:

firebase.auth().settings.appVerificationDisabledForTesting = true;

Firebase docs

https://firebase.google.com/docs/auth/web/phone-auth?authuser=0#web-v8_6

// Turn off phone auth app verification.
firebase.auth().settings.appVerificationDisabledForTesting = true;

var phoneNumber = "+16505554567";
var testVerificationCode = "123456";

// This will render a fake reCAPTCHA as appVerificationDisabledForTesting is true.
// This will resolve after rendering without app verification.
var appVerifier = new firebase.auth.RecaptchaVerifier('recaptcha-container');
// signInWithPhoneNumber will call appVerifier.verify() which will resolve with a fake
// reCAPTCHA response.
firebase.auth().signInWithPhoneNumber(phoneNumber, appVerifier)
    .then(function (confirmationResult) {
      // confirmationResult can resolve with the fictional testVerificationCode above.
      return confirmationResult.confirm(testVerificationCode)
    }).catch(function (error) {
      // Error; SMS not sent
      // ...
    });

method 2:

https://firebase.google.com/docs/auth/web/phone-auth#use-invisible-recaptcha

window.recaptchaVerifier = new firebase.auth.RecaptchaVerifier('sign-in-button', {
  'size': 'invisible',
  'callback': (response) => {
    // reCAPTCHA solved, allow signInWithPhoneNumber.
    onSignInSubmit();
  }
});