Automate email verification testing in Playwright (links + OTPs)

When did you last create an account that didn’t require you to supply an email address?

Email verification is still one of the most common final steps in signup flows. It’s also one of the easiest places for bugs to hide: messages that never arrive in staging, OTP codes that work, or verification links that break when environments change.

If you’re using Playwright, you can automate the full flow, including account verification emails, OTPs, and password reset links, without relying on a shared Gmail inbox or using a personal phone.

This guide shows a clean, scalable way to do it with Mailosaur as your email testing tool.

Can Playwright test email verification by itself?

Playwright has proven to be a massively popular and effective tool for browser automation and web app testing, but it hasn’t been designed to capture and evaluate emails by itself.

Without an additional tool, you can use Playwright to navigate to a webmail client like Gmail and try to pull content out that way, but this is time-consuming, error-prone, and limits the number of email addresses you have easy access to. This will inevitably limit testing and increase the chance of issues not being spotted and fixed, as well as leaving you susceptible to problems such as cross-test collisions and flaky CI runs.

So, while Playwright does technically work, in essence it forces you to manually test the email verification process on a regular basis, rather than using large scale, automated systems to spot issues.

This is where an email testing tool such as Mailosaur comes in- giving you the ability to automate email tests with an unlimited number of test email addresses, for a more complete view of the email account verification process and even options to preview your emails before you hit send.

How to use Playwright for account verification testing

Playwright can efficiently run the tests you need if you add in a tool, such as Mailosaur. Integration is quick, simple, and effective. It gives you the ability to automate email tests with an unlimited number of test email addresses, for a more complete view of the email account verification process.

Run tests to check any link sent to an email works as intended, which you can use for account creation, or closure processes. Whatever works for you. In the same vein, if you choose to send a verification code in your email, it’s easy to extract it for testing purposes.

Start with a simple Playwright project

Before you begin, you can generate a basic starter project, including Mailosaur integration, which will install and set up Mailosaur:

npm create mailosaur@latest

For more detailed instructions, or to manually integrate Mailosaur with an existing project, check out the full guide in our documentation.

Running email verification tests with Playwright

Running email verification tests is simple. Here’s a quick example:

const apiKey = 'API_KEY';
const serverId = 'SERVER_ID'; // The unique ID of the inbox (server) that you are using

// Instantiate Mailosaur client with api key
const mailosaur = new MailosaurClient(apiKey);

test('Verify email using OTP code via email', async ({ page }) => {
  // Random test email address (this uses a catch-all pattern)
  const randomString = (Math.random() + 1).toString(36).substring(7);
  const emailAddress = `${randomString}@${serverId}.mailosaur.net`;

  // 1 - Attempt to signup, this should trigger an OTP code to be sent to 'emailAddress'

  // 2 - Create the search criteria for the email
  const searchCriteria = {
    sentTo: emailAddress,
  };

  // 3 - Get the email from Mailosaur using the search criteria
  const email = await mailosaur.messages.get(serverId, searchCriteria);

  // 4 - Retrieve passcode from the email
  const passcode = email.html.codes[0];

  // 5 - Use the passcode to verify your email address
});

Links

The crucial part here is the link or verification code inside the email itself. If it doesn’t work, your account verification process won’t either. Whether you choose a link or a verification code, Mailosaur can automatically detect and extract what you need.

 // 1 - Attempt to signup, this should trigger a verification link to be sent to 'emailAddress'
 
 // 2 - Create the search criteria for the email

// 3 - Get the email from Mailosaur using the search criteria
  
// 4 - Extract link from the email
const link = email.html.links[0].href;

// 5 - Verify your email address