In web development, you get one shot to hit every popular browser and device. One missed bug or flaw can grow into a larger problem or cause significant issues at launch. Quality assurance (QA) testers have two valuable tools to help make sure websites and applications perform seamlessly across browsers and devices, and understanding the advantages and limitations of these tools is essential when performing QA work.

Browser emulators and plugins are like cheat codes for testers–they’re agile and flexible, and allow for rapid testing across a wide range of scenarios. Browser emulators and plugins also help isolate testing to create environments that optimize debugging and are efficient, cost-effective tools that must be in every QA firm’s toolkit.

A user working at their desk on an iPad device. In front of them is a Macbook laptop using a web browser.


Understanding Browser Emulators

What is a Browser Emulator?

A browser emulator is a versatile tool that enables developers and testers to mimic the appearance and functionality of a website on specific browsers. This emulation process allows for a detailed examination of the site’s performance under various conditions, offering customization options such as operating systems, browser types, and screen resolutions.

Advantages of Browser Emulators

Diverse Testing Environment

Browser emulators excel in providing a diverse testing environment, allowing users to simulate a wide range of conditions. This capability is invaluable for thoroughly examining how websites respond to different scenarios, ensuring comprehensive testing coverage.

Efficiency and Cost Savings

One of the critical advantages of browser emulators is their efficiency in testing. Unlike traditional methods that require switching between multiple devices, emulators operate on a single device. This streamlines the testing process and significantly reduces costs associated with acquiring and maintaining a collection of physical devices.

Illustration of a browser window with an icon representing 'code' implying that it is being emulated.


What is a Plugin?

A browser plugin is a dynamic tool seamlessly integrated into web browsers, enhancing the capabilities of developers and testers. It introduces an additional layer of functionality to the testing toolkit, providing a suite of features to augment the testing process. These add-ons empower testers to extend the browser’s capabilities, enabling specialized testing tasks and checks beyond the standard browser functionalities.

Advantages of Plugins

Enhanced Testing Scenarios

Plugins unlock the potential for testers to create intricate testing scenarios by introducing specialized tools and features. Whether it’s performance profiling, security checks, or accessibility testing, plugins elevate the testing process by providing specialized testing capabilities.

Seamless Workflow Integration

An inherent advantage of browser plugins is their seamless integration into the testing workflow. Testers can harness these tools directly within the browser environment, eliminating the need for external applications and simplifying the overall testing process.

Customization for Unique Testing Needs

Plugins are adaptable to unique testing requirements. Testers can configure and select plugins that align with the specific needs of their projects, ensuring a customized and efficient testing strategy.

Optimizing Development Efficiency

In tandem with emulators, plugins significantly contribute to the efficiency of the testing process. Plugins optimize the development workflow by streamlining access to specialized testing tools and features, allowing testers to identify and address issues swiftly.

Illustration of a browser window with an icon representing 'plugin' implying that it is using a plugin.


Limitations of Browser Emulators and Plugins

While browser emulators offer a close approximation of how a website will behave on specific browsers and devices, it’s essential to acknowledge their limitations. Emulators may not perfectly replicate the exact configurations of real devices. However, they prove highly effective in identifying significant issues during the testing phase. Real devices remain superior for problems that may not be reliably produced by emulation, making a combined approach of emulator and real device testing optimal for comprehensive quality assurance. Emulators play a vital role in catching potential problems early in the development cycle, allowing for swift resolution and a smoother user experience in the final product.


Popular Browser Emulators and Plugins

Mobile Simulator

The Mobile Simulator is a versatile Chrome Web Store plugin designed to simulate the user experience on various mobile and tablet devices. This plugin offers a comprehensive range of 52 devices for responsive testing, including recent models like the Galaxy S22 and iPhone 15 (Pro & Max), enabling testers to mimic real-world conditions. Beyond smartphones, it also supports tablets and special devices like the Apple Watch, a Self-Service Kiosk, and even a MacBook. While the plugin is free, a non-intrusive advertisement is displayed unless the premium version is purchased.

Screenshot of Mobile Simulator plugin.

Source: Mobile Simulator

Responsive Viewer

Responsive Viewer, another Chrome Web Store plugin, goes beyond traditional responsive testing. It allows users to test how a website displays on various screen sizes and view each screen size simultaneously. This feature is beneficial for identifying visual bugs or errors that may arise due to changes in screen window resolution. The simultaneous viewing capability streamlines the bug identification process, contributing to a more efficient testing workflow.

Screenshot of Responsive Viewer plugin.

Source: Responsive Viewer


Playwright stands out as a cross-browser, cross-platform, and cross-language browser emulation API suite. It provides a robust solution for reliable end-to-end testing of modern web applications. Playwright can test an application on any browser and emulate real mobile phones or tablets. With a registry of device parameters using Playwright, testers can simulate browser behavior for specific devices, including user agent, screen size, viewport, and touch capabilities. Playwright is not limited to functional testing; it also excels in accessibility testing, helping identify issues such as poor color contrast, unlabeled UI controls, and duplicate interactive elements.

Screenshot of Playwright product website.

Firefox Responsive Design View

Firefox’s Responsive Design View is a built-in tool that encourages developers to avoid thinking about specific devices. Instead, it promotes exploring how designs change at common screen sizes or custom sizes by dragging the edges. This tool is part of Firefox’s developer tools and provides a flexible approach to responsive design testing.

Screenshot of Firefox Responsive Design View tool in-use.

Source: Firefox Source Docs


Cloud-Based Emulators and Simulators


BrowserStack is a commercial cloud-based emulator renowned for its user-friendly interface. It simplifies manual testing by allowing users to select an operating system, browser version, and device type. Once selected, it spins up a hosted virtual machine that testers can interact with. It supports multiple emulators on the same screen, enabling simultaneous testing across various devices.


Another commercial solution, SauceLabs, can run unit tests inside an emulator. This feature is handy for scripting a flow through a website and watching the video recording of this process on various devices. SauceLabs also supports manual testing, providing a comprehensive testing environment.

Device Anywhere

Device Anywhere takes a unique approach by utilizing real devices that testers can control remotely. This is especially beneficial when it’s necessary to reproduce a problem on a specific device, and the bug is not visible on other emulators or simulators. Having access to real devices enhances the accuracy of testing.


LambdaTest is a commercial tool designed for manual cross-browser testing. With support for over 2000 browsers and operating systems, users can perform extensive tests to ensure their websites function seamlessly across diverse environments. The tool allows recording videos of complex bugs. The videos can be shared through integrations with platforms like MS Teams and Slack. Additionally, users can speed up testing by running tests in parallel.

Edge’s F12 Emulation

Microsoft Edge’s F12 Developer Tools feature includes an Emulation tool that allows developers to emulate different environments where web pages can be viewed. This tool is particularly valuable for catching and debugging issues early in the development cycle. It provides flexibility in emulating various conditions and contributes to a more comprehensive testing strategy.

AWS Device Farm

Amazon Web Services Device Farm is a tool that allows users to test their web and mobile apps on many different browsers or devices in the AWS cloud. The device farm can run multiple devices and browsers at the same time, without the need for having them physically, and can simulate real-world user environments. Users can set up their own private device lab and can run tests manually or by utilizing built-in test suites to identify and resolve issues quickly.


Comprehensive Testing

By incorporating various browser emulators and plugins into their testing, quality assurance analysts can ensure that web applications function seamlessly and maintain visual appeal across browsers and devices. They help identify potential issues early in the development cycle, paving the way for a more refined and user-friendly web experience.

PLUS QA utilizes browser emulators and plugins as part of our comprehensive approach to quality assurance testing; these tools are especially effective early in testing to catch bugs and flaws while they’re easily manageable, and we then test again with real devices to ensure our analysts have the same experiences as our clients’ users. If you want to learn more about the kinds of testing we offer, please reach out today.

Image of a laptop, plant, and mug on a desk. Laptop has website code on the screen.