Playwright

Overview

Playwright is a modern, open-source end-to-end testing framework created by Microsoft. It enables automated testing of web applications across multiple browsers (Chromium, Firefox, WebKit) with a single API.

It is designed to be:

• Reliable
• Fast
• Cross-browser
• Suitable for both UI and API interactions
• Easy to run in CI/CD pipelines
• Extremely stable due to auto-waiting and built-in retries

Playwright tests typically run in Node.js, but the framework also supports:

• C# (.NET bindings)
• Python
• Java
• TypeScript/JavaScript (most common)

What Problem Does Playwright Solve?

Playwright addresses the main problems of earlier UI test frameworks like Selenium, including:

Problem	Solution
Flaky tests	Playwright solves this using auto-waits, smart timeouts, and deterministic handling of events.
Inconsistent browser behaviour	Playwright ships with patched browser binaries for consistent cross-browser execution.
Slow feedback loops	Playwright runs fast, supports parallel execution, and has a robust CLI.
Hard-to-maintain test code	Playwright supports Page Object Models, fixtures, and reusable components.

Key Features

Feature	Explanation
Cross-browser support	Chromium Firefox WebKit Android / Mobile emulation
Auto-waiting	Playwright automatically waits for elements to be visible, ready, stable, and actionable. Huge advantage
Fast parallel execution	Built-in test runner parallelises by default.
Powerful selectors	CSS, XPath, text selectors, role selectors, test-ids, and more.
API testing support	You can test web APIs without a browser.
Network mocking / interception	Mock responses, block calls, simulate network conditions, etc.
Visual, screenshot, and trace testing	Fully integrated tooling for debugging failed tests.
Works with modern web apps	Designed for React, Blazor, Angular, Vue, etc.

Typical Use Cases

Use Case	Explanation
Web UI Testing (primary use case)	Verify the full UI flow of your application in multiple browsers.
API Testing	Simulate backend API calls without UI overhead.
Component Testing	Especially useful in modern SPAs.
Visual Regression Testing	Take consistent screenshots for pixel-diff checking.
Performance or Load Profiling	Not its primary job, but useful for network-level throttling simulations.

Example Playwright Test in C# (.NET)

using Microsoft.Playwright;
using System.Threading.Tasks;
using Xunit;

public class LoginTests
{
    [Fact]
    public async Task UserCanLogIn()
    {
        using var playwright = await Playwright.CreateAsync();
        await using var browser = await playwright.Chromium.LaunchAsync(new BrowserTypeLaunchOptions
        {
            Headless = true
        });

        var context = await browser.NewContextAsync();
        var page = await context.NewPageAsync();

        await page.GotoAsync("https://example.com/login");
        await page.FillAsync("#username", "testuser");
        await page.FillAsync("#password", "password");
        await page.ClickAsync("button[type=submit]");

        await page.WaitForSelectorAsync("text=Welcome testuser");
    }
}

Key points:

• Headless browser
• Auto-waits on all interactions
• Cross-browser with minimal changes

Advantages of Playwright

• Extremely reliable tests - Auto-waiting significantly reduces flaky failures.
• Supports modern JS frameworks - Handles shadow-DOM, iframes, single-page apps very well.
• Cross-browser with one API - No separate drivers needed (unlike Selenium WebDriver).
• Fast execution - Parallelisation and browser contexts reduces overhead.
• Rich debugging toolkit - Trace viewer, screenshot comparison, video recordings.
• First-class support for CI/CD - Works well with GitHub Actions, Azure DevOps, GitLab, and others.
• Supports C#, Java, Python - Good for mixed-stack organisations.

Disadvantages and Limitations

• Node.js-based ecosystem - .NET support is strong but not as mature as TypeScript/JS.
• Not a load-testing tool - It’s E2E and functional testing focused.
• Requires familiarity with async programming - Everything is asynchronous.
• UI tests are inherently slower than unit or integration tests - though Playwright is faster than most alternatives.
• Learning curve for selectors and fixtures - Especially the built-in test runner.

Playwright vs Selenium

Feature	Playwright	Selenium
Auto-waiting	Yes	No
Speed	Fast	Slower
Cross-browser	Built-in	Requires external drivers
Modern web app support	Excellent	Mixed
API testing	Yes	No
Mobile testing	Emulation	Real devices via Appium
Ease of setup	Very easy	More configuration
Language support	JS/TS, C#, Python, Java	Broad

Playwright is generally better for modern UI testing. Selenium still wins for real mobile devices and legacy support.

Playwright vs Cypress

Feature	Playwright	Cypress
Browser support	All major browsers	Chromium & Firefox only
Debugging	Excellent	Excellent
Network mocking	Strong	Strong
Parallel runs	Built-in	Paid tier for dashboards
Speed	Faster	Slower
API testing	Full	Full
Language	JS/TS, C#, Java, Python	JS only

Summary

Playwright is a modern cross-browser web testing framework built for reliability, speed, and ease of use.

Playwright reduces flakiness with auto-waiting, supports multiple browsers, integrates well with CI/CD, and includes powerful debugging tools like trace view and network inspection.

Teams choose Playwright when they need deterministic, stable, fast UI tests that work well with modern applications and multiple browsers.