Test Firebase Authentication emails

Limits below are from Firebase’s Authentication limits page on 17 October 2026. Check it for current details.

What Firebase sends

Each is a link. The 5-a-day limit on email-link sign-in catches most teams testing passwordless sign-in on the free plan: after five, the emails stop until the next day.

Test it by hand

1. Create an address in Proxy Mail QA.
2. Sign up in your app with it, or request an email sign-in link.
3. The link appears on the address’s row within seconds. Open it in the browser where you started, as email-link sign-in expects.

Check the link lands on your app, not localhost: the continue URL comes from your code, and its domain must be in Authentication → Settings → Authorized domains.

Automate it

import { test, expect } from 'proxymail-qa/playwright';

test('Firebase sign-up verifies the address', async ({ page, qa }) => {
  const { address, password } = await qa.createAddress({ password: true });
  const submitted = new Date();
  await page.goto('/signup');
  await page.getByLabel('Email').fill(address);
  await page.getByLabel('Password').fill(password);
  await page.getByRole('button', { name: 'Create account' }).click();

  const { value: link } = await qa.waitForLink(address, { type: 'verify', since: submitted });
  await page.goto(link);
  await expect(page.getByText('Your email has been verified')).toBeVisible();
});

For mobile apps, see Firebase email-link sign-in for mobile apps. Built with Antigravity? Its guide covers the Firebase settings it sets up. More in Test sign-up emails in Playwright.