Mastering Multiple Logins with Playwright

End-to-end testing often requires simulating different user roles—admin, customer, or moderator—on a web application. Manually logging in each time can be inefficient, and reusing sessions improperly can lead to flaky tests. Fortunately, Playwright provides powerful tools to handle multiple logins seamlessly.

Playwright is a powerful Node.js library for browser automation it provides a robust solution for testing across different contexts

In this guide, we’ll explore:

How Playwright manages multiple user sessions.
Setting up browser contexts for isolated logins.
Best practices

Let’s dive in!

Understanding Browser Contexts in Playwright

Playwright introduces browser contexts, which allow us to create isolated browser instances within a single test. Each context operates independently, meaning cookies, local storage, and session data don’t leak between them.

Instead of opening multiple browsers (which is slow), Playwright lets us create various contexts within the same browser, making multi-user testing efficient.

Why are they Important?

Handling multiple logins effectively in Playwright is essential for testing real-world applications where different users interact with the system. Here’s why it comes in handy:

Testing User Roles: Many applications have different user types (e.g., admins, customers, moderators). The playwright’s multi-login approach allows verifying role-based access controls.
Parallel Testing: Running multiple sessions in a single browser instance improves test efficiency compared to launching separate browsers.
Avoiding State Contamination: Isolating browser contexts ensures that one test doesn’t interfere with another, leading to more reliable results.
Speeding Up Test Execution: By reusing authentication states, login processes are skipped, reducing test runtime significantly.

This approach ensures robust and scalable test automation, making your workflow more efficient.

Setting Up Playwright for Multi-User Tests

Before implementing multiple logins, ensure Playwright is installed:

npm init playwright@latest

Now, let’s create a basic Playwright test file:

import { test, expect } from '@playwright/test';

test('Multiple users can log in independently', async ({ browser }) => {
    // Create two independent browser contexts
    const userContext1 = await browser.newContext();
    const userContext2 = await browser.newContext();

    // Create pages for each user
    const userPage1 = await userContext1.newPage();
    const userPage2 = await userContext2.newPage();

    // User 1 logs in
    await userPage1.goto('https://example.com/login');
    await userPage1.fill('#email', 'user1@example.com');
    await userPage1.fill('#password', 'password123');
    await userPage1.click('button[type=submit]');

    // User 2 logs in
    await userPage2.goto('https://example.com/login');
    await userPage2.fill('#email', 'user2@example.com');
    await userPage2.fill('#password', 'password456');
    await userPage2.click('button[type=submit]');

    // Verify each user sees their respective dashboard
    await expect(userPage1).toHaveURL('https://example.com/dashboard');
    await expect(userPage2).toHaveURL('https://example.com/dashboard');

    // Close contexts
    await userContext1.close();
    await userContext2.close();
});

The above code snippet ensures that:

Each user logs in separately.
Session data does not mix between users.
Both users navigate to their respective dashboards successfully.

Best Practices

✅ Use browser contexts instead of multiple browsers – Faster and more efficient.

✅ Save and reuse authentication state – Avoid unnecessary logins.

✅ Isolate session data properly – Prevents test contamination.

❌ Don’t rely on global state – Each test should be independent.

❌ Avoid hardcoding credentials – Use environment variables instead.

Playwright makes handling multiple logins straightforward by using browser contexts

By applying this technique, you can:

Simulate multiple users efficiently.
Ensure reliable and independent test runs.

Are you using Playwright for multi-user tests? Share your experience in the comments!

For Further Reading Check Out https://playwright.dev/docs

Handling Multiple Logins in Playwright Like a Pro

Understanding Browser Contexts in Playwright

Why are they Important?

Setting Up Playwright for Multi-User Tests

Best Practices