Comparison of Playwright vs Selenium: Differences & Examples

Automated testing plays a vital role in software development by helping organizations deliver high-quality software at speed and scale.

As applications grow larger and more complex, manual testing cannot keep up with the pace of development. Automated testing helps ensure features and functionality continue to work as intended with each new change to the codebase. It allows developers to test more often and catch bugs earlier in the development process.

Two of the most popular frameworks for automating UI tests are Playwright and Selenium. Playwright and Selenium allow developers to script automated tests that interact with a website or app as a user would. They can click buttons, fill out forms, and validate content and behavior across different browsers and operating systems.

This guide will provide an in-depth comparison of Playwright vs Selenium. Key factors like supported browsers, programming languages, ease of use, assertion capabilities, and test speed will be examined. After reviewing the capabilities and limitations of each framework, developers will better understand which may be the best fit for their specific testing needs and project requirements.

Playwright vs Selenium

Playwright and Selenium are both open-source tools used to automate browser testing. They allow you to write tests that simulate user actions like clicking buttons, filling out forms, and navigating web pages. These tests can then be run on a schedule or triggered by code changes to catch bugs and regressions.

Choosing between Playwright vs Selenium is an important decision that can impact your test automation’s quality, speed, and reliability. While they have some overlap, there are also key differences in their approaches.

This guide will compare Playwright and Selenium across the following aspects:

• Background and history
• Supported languages and browsers
• Test runner and framework options
• Selectors and locators
• Built-in waits and synchronization
• Mobile device testing
• Native app testing
• Speed and reliability
• Parallel testing
• Visual testing
• Developer experience

Understanding these similarities and differences will help you determine which UI automation tool fits your needs better.

Background and History: Playwright & Selenium

Playwright

Playwright is a relatively new entrant in end-to-end testing, first released by Microsoft in 2019. It is an open-source Node.js library that provides a single API for automating Chrome, Firefox, and WebKit browsers.

Playwright was created by former members of the Puppeteer team at Google. It builds on the foundations of Puppeteer but expands the scope beyond just Chromium. The goal is to provide a consistent API for automation across multiple browsers.

Since launching, Playwright has seen rapid adoption by web teams and has been welcomed as a modern alternative to Selenium-based testing. While it is less battle-tested than Selenium, Playwright benefits from its young age by having a clean, well-designed API.

Selenium

Selenium emerged in 2004 as a JavaScript library for automating the Firefox browser. However, it gained widespread popularity after the Selenium WebDriver release in 2009. WebDriver expanded the scope beyond Firefox and provided an interface for driving all major web browsers.

Today, Selenium is the most established end-to-end testing framework. It benefits from over a decade of development and real-world usage. Selenium powers the test automation efforts of many large enterprises. It also integrates with all popular unit testing frameworks like JUnit and TestNG.

The downside to Selenium’s maturity is dealing with dated components and legacy browser driver code. The playwright offers a chance to start fresh with modern architecture.

Supported Languages and Browsers of Playwright vs Selenium

Both Playwright and Selenium support a range of languages for writing tests. They also enable automation across all commonly used web browsers. However, there are some differences in their level of support.

Languages

Playwright supports JavaScript, TypeScript, Python, .NET, and Java out of the box. Users can also call the Playwright API directly from other languages like PHP, Ruby, and C#.

Selenium has official bindings for Java, C#, Python, JavaScript, Ruby, PHP, and Perl. There are also community-supported libraries for Go, R, Swift, and other languages.

Browsers

Playwright can automate Chromium, Firefox, and WebKit browsers. This allows you to test on Google Chrome, Mozilla Firefox, Microsoft Edge, and Apple Safari.

Selenium supports the same browsers through ChromeDriver, GeckoDriver, and SafariDriver. It previously automated Internet Explorer via IEDriver, but this browser has been deprecated.

Both tools enable testing headless browsers to speed up execution. They also let you specify browser versions and channels (stable, beta, etc) as needed.

Overall, Playwright and Selenium are on par for language support. Playwright has a smaller browser footprint but covers the most common targets.

Test Runner and Framework Options

An automation framework handles running tests and reporting results. Playwright and Selenium can integrate with unit testing frameworks like Jest, Mocha, and JUnit. However, Selenium has more built-in options, while Playwright relies on 3rd party tools.

Playwright

Playwright is designed as a library to enable browser automation. It does not include built-in capabilities for running test suites or generating reports.

Instead, developers use Playwright with test runners like Jest, Mocha, Jasmine, or Cucumber. The tests can also be run through CI tools like GitHub Actions, CircleCI, and Jenkins. Some fledgling tools like TestProject aim to provide a complete framework around Playwright.

The benefit of this approach is developers have full control over picking test runners and reporting tools they are already familiar with. The downside is the lack of an integrated solution out-of-the-box.

Selenium

In contrast to Playwright, Selenium offers its own ecosystem of test runners like Selenium Grid and Selenium IDE.

Selenium Grid allows distributing tests over multiple machines for faster parallel execution. Selenium IDE is a recorder and test editor integrated directly into the browser.

In addition, 3rd party tools like Katalon Studio and Tricentis Tosca provide commercial frameworks and dashboards around Selenium. Open source runners like Gauge and Robot Framework are built to make test authoring easier.

Overall, Selenium provides richer options for those seeking an integrated automation environment. But developers who want to extend their existing test runners may lean towards Playwright’s flexibility.

Selectors and Locators

Selectors are used to target DOM elements in Playwright and Selenium scripts. Both tools support CSS selectors along with some special selectors for enhanced precision.

Playwright Selectors

The playwright uses the following selector strategies:

• CSS: Standard CSS query selectors like .class-name and #id
• Text: Match elements containing specific text
• Visibility: Select only visible or hidden elements
• Editable: Match input fields based on editability
• Attributes: Target elements with a given attribute name and value

In addition, Playwright can chain together multiple selectors to create unique combinations.

Selenium Locators

Selenium supports the following built-in locator strategies:

• ID: Locate by element ID attribute
• Name: Match elements by name attribute
• Class name: Target elements with specific CSS class
• Tag name: Select by HTML tag
• Link text: Partial matches on link text
• CSS: CSS selector queries
• XPath: Full XPath expressions

Selenium also allows combining multiple locators for advanced selections.

Overall, Playwright and Selenium have similar capabilities for targeting web page elements. Playwright’s selector API is a bit cleaner while Selenium offers some additional options like XPath.

Built-in Waits and Synchronization

Website testing often requires waiting for elements or pages to load fully before interacting. Playwright and Selenium both have built-in utilities for handling waits and synchronization.

Playwright Waits

Playwright avoids the need for most explicit waits through its auto-wait mechanism. By default, commands will poll the DOM and wait for elements to become available up to a timeout limit:

// Waits up to 30 seconds for element
await page.click('button');

Advanced use cases can leverage options like waitForSelector() to wait for an element explicitly. Checks like locator.isVisible() Confirm visibility before acting.

Selenium Waits

Selenium requires more explicit wait management from test scripts. Common approaches include:

• WebDriverWait for waiting until a condition is true
• time.sleep() to pause execution for a duration
• element.is_displayed() to check visibility

There are also expected conditions like presence_of_element_located() That can be used with waits.

While Playwright’s auto-wait behavior reduces boilerplate code, Selenium gives developers precise control over synchronization logic.

Mobile Device Testing

Testing web interfaces on mobile devices is important to ensure responsiveness. Playwright and Selenium have varying levels of support for automating mobile browsers.

Playwright Mobile Testing

Playwright enables mobile web testing by emulating device screens and hardware. For example:

const iPhone = devices['iPhone 11 Pro'];

const browser = await chromium.launch({
  ...iPhone, // Emulate iPhone screen and touch events
});

However, Playwright does not allow controlling real mobile devices connected to the machine. Automating native mobile apps is also not supported.

Selenium Mobile Testing

Selenium offers a few options for mobile test automation:

• Appium: Mobile app testing framework using Selenium wrappers
• Selenium Grid: Supports integration with real device cloud services
• Emulators: Can mimic mobile screens like Playwright

Thus, Selenium provides both native app control through Appium and options for mobile web testing.

Overall, Selenium has more robust support for executing tests across mobile devices and platforms.

Native App Testing

For testing native desktop and mobile applications, Playwright is limited, while Selenium offers integration through Appium.

Playwright

Playwright only supports testing web content rendered through a browser engine like Chromium, Firefox or WebKit. It cannot interact with standalone native apps.

Selenium

Appium enables Selenium to automate the testing of mobile and desktop apps through an extension of the WebDriver protocol. This allows for the control of native apps on platforms like iOS, Android, and Windows.

Selenium even enables testing mobile apps hosted in an emulator/simulator without the need for a real device. Overall, it provides extensive functionality for driving native apps that Playwright lacks.

Speed and Reliability

Speed and reliability are key considerations for test automation. Faster test execution provides quicker feedback, while robustness ensures tests pass consistently.

Playwright Speed

Playwright offers extremely fast execution speed by default, running tests in a lightweight browser context. Operations like opening pages and grabbing screenshots are significantly faster than Selenium in benchmark tests.

This speed advantage is due to Playwright’s trimmed-down browser environments and asynchronous execution. Tests will naturally run much faster when not slowed down by rendering visual content.

Selenium Speed

Selenium 4 introduces a new WebDriver BiDi protocol that improves communication efficiency between browser drivers. This helps reduce overhead and latency compared to earlier versions.

However, Selenium is still inherently slower than Playwright since it runs tests in a real browser. Performing actions like opening websites requires full page loads. Headless mode improves speed but not to Playwright’s level.

Reliability

Playwright’s reliability is still being established, given its newness. However, the architecture shows promise for stability over time.

Meanwhile, Selenium has proven its robustness through over a decade of real-world testing across industries. The community establishment gives it an edge for reliability today.

Both tools are under active development, so reliability should continue improving. Ultimately, Selenium still inspires more confidence, but Playwright may catch up with maturity.

Parallel Testing

Running tests in parallel across multiple machines is crucial for achieving fast test execution. Both Playwright and Selenium offer parallelization capabilities.

Playwright Parallel Testing

Playwright enables parallel test execution through built-in tools like testRunners and integration with 3rd party runners.

For example, the following splits tests across processes using the jest-puppeteer-test-runner module:

const { testRunners } = require(`@playwright/test-runner`);

module.exports = testRunners.jest({
  // Run 4 workers in parallel 
  workers: 4,
});

CI systems like GitHub Actions also make it straightforward to run Playwright tests concurrently across distributed machines.

Selenium Parallel Testing

Selenium Grid is the standard tool for executing Selenium tests in parallel. It works by distributing tests over a farm of nodes that run browsers independently.

Grid supports parallelization across hundreds of machines along with dynamic scaling. Cloud offerings like Zalenium even provide a managed Grid to simplify distributed execution.

In addition, Selenium 4 introduces built-in Chromium and Firefox pools that spin up multiple isolated browser instances on one machine.

Overall, both frameworks offer excellent parallel testing options – Selenium with Grid and Playwright through CI tools and npm libraries.

Visual Testing

Visual testing compares screenshots to detect UI changes over time. Playwright and Selenium both enable capturing and asserting against screenshots.

Playwright Screenshots

Playwright includes built-in utilities for taking page screenshots that can be used for visual testing:

// Save screenshot to disk
await page.screenshot({ path: 'page.png' });

// Compare screenshot to baseline 
expect(await page.screenshot()).toMatchSnapshot('landing-page');

The community package jest-playwright-png further simplifies visual snapshot testing with Jest.

Selenium Screenshots

Selenium also provides methods for capturing screenshots on demand:

// Take screenshot
File screenshot = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE); 

// Compare images
assertThat(baseline, sameAs(screenshot));

Libraries like AShot simplify screenshot comparisons for visual testing with Selenium.

Both tools provide straightforward screenshot capture along with community packages for image assertions. Overall, visual testing capabilities are on par.

Developer Experience

Developer experience compares API design, debugging, documentation and other factors impacting test creation.

Playwright DX

Playwright offers an improved developer experience versus Selenium:

• Modern API: Intuitive, promise-based JavaScript API
• REPL browser: Interactive playground for trying selectors
• Trace Viewer: Explore test run visually
• Debugging: Native browser devtools support
• Documentation: Concise API reference and user guide

The REPL browser provides a unique way to build locators that isn’t possible in Selenium interactively. Overall, Playwright delivers a polished developer experience that facilitates test creation.

Selenium DX

While Selenium is very capable, its developer experience has room for improvement:

• Overloaded API: Many classes and managers to juggle
• Page objects: Required for abstraction and reuse
• Element tools: Lack built-in locator playground
• Debugging: DevTools integration varies by language
• Docs: Spotty with some outdated sections

Test code can become complex fast due to Selenium’s lack of opinionated structure. Documentation and tutorials are also inconsistent in quality.

Conclusion

This comprehensive feature comparison highlights the key similarities and differences between Playwright and Selenium.

Playwright stands out for its speed, simple API, and polished developer experience. It offers a fast path to start test automation using modern JavaScript and TypeScript stacks.

Selenium remains the more mature and battle-tested solution. Its ecosystem provides rich integrations, mobile testing, and parallelization capabilities that Playwright currently lacks.

Here is a quick summary of the main points:

• Playwright has a clean, modern API while Selenium is hampered by legacy baggage
• Both support all major languages; Selenium has more framework integrations
• Playwright auto-waits reduce boilerplate; Selenium offers more control
• Selenium enables robust native and mobile app testing through Appium
• Playwright executes tests significantly faster by default
• Selenium is proven and reliable at scale after years of use
• Parallel execution is easily achievable with both tools
• Visual testing features are on par with frameworks
• Playwright provides a smoother developer experience overall

The right choice comes from your team’s skills, browser needs, and testing priorities. For greenfield browser automation needs, Playwright is worth considering. But Selenium remains a solid option, especially for large enterprises with an established framework.

Hopefully this detailed Playwright vs Selenium comparison provides insight into which solution may work best for your use case. Both tools empower teams to ship higher-quality software through test automation.

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