How to send Firebase paswordless login link? - firebase

Question

I am trying to implement magic link login to my app. I enabled email login option through Firebase console and localhost is already under the authorized domains. I have the code snippet and the screenshot in the below.
I can see that some request is being done with 200 success code but I receive no email.The code does not throw any error and I have no idea what is wrong at this point. Can someone help?
export const sendMagicLink = (email: string, redirectUrl: string) => {
const auth = getAuth(getClientApp());
const actionCodeSettings = {
url: redirectUrl,
handleCodeInApp: true
};
return sendSignInLinkToEmail(auth, email, actionCodeSettings);};
const handleSubmit: svelte.JSX.EventHandler<SubmitEvent, HTMLFormElement> = async ({
currentTarget
}) => {
email = new FormData(currentTarget).get('email') as string;
const redirectUrl = `${window.location.origin}/auth/confirm`;
state = 'submitting';
try {
await sendMagicLink(email, redirectUrl);
setMagicEmail(email);
state = 'success';
} catch (error) {
if (error instanceof Error) {
state = error;
} else {
console.log(error);
state = new Error('something went wrong sending the magic link 😞');
}
}
};
Request body:
canHandleCodeInApp true
continueUrl "http://localhost:3000/auth/confirm"
email "someemail#gmail.com"
requestType "EMAIL_SIGNIN"

Answer 1

Intuitively a developer assumes that emails sent out by Firebase's internal email service will not be classified as spam, but this happens very often.
To solve this, one would need to:
Setup a custom domain for Authentication in Firebase Console
Go to Firebase Authentication
Go to Templates
Go to Email Address Verification
Click Edit
Click Customize domain and go through the whole process
Setup a proper SMTP server in Firebase Console
Go to Authentication
Go to Templates
Go to SMTP Settings and enter SMTP Settings. Use the same sender domain as has been used in Email Address Verification above.
Setting Action URL
Set your custom domain in the Hosting section, first, e.g.: example.com.
Then, in the Authorization Templates section, click Edit and adjust the Custom Action URL at the bottom of the page. Set it to the same domain used for Hosting, e.g.:
https://example.com/__/auth/action
This helps to decrease the spam ranking of the emails, as the outgoing email from domain A will now contain a link to domain A.
In contrast, an email from domain A carrying a link to domain B is more suspicious.