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Top 7 UI Responsiveness And Performance Testing Tools

William Tsu
Data Analyst
Experienced data analyst working with data visualization, cloud computing and ETL solutions.
December 26, 2020

We are living in an information-rich digital world; and on a daily basis, we interact with different types of content that are available through various devices such as smartphones, laptops, desktop computers, tablets, etc. When it comes to websites, a majority of audiences prefer the layout of the website to be the same across all devices.

But how will you make your website render a consistent browser experience irrespective of the type of device used by the customers?

This is where responsive web designing plays a role in meeting the expectations of the vast user community. Responsive Web Design - RWD is the latest web design approach that enables the website to render a consistent browsing experience throughout all the devices. Scaling your website across all devices, irrespective of screen resolutions and screen sizes retains your customers and can significantly increase your bottom line. Hence, to transform a website into a multi-device site, designers and developers need to adopt an efficient Responsive Web Design approach.

Does adopting an RWD approach the only thing that we need to do for building an outstanding multi-device site?

No, to develop an interactive website that responds similarly to each device used by customers all over the world, we need to test the UI responsiveness and performance of the website. But understand that it's really expensive to build and maintain Android, iOS, Windows, Blackberry, and other device labs exclusively for testing the responsiveness and performance of websites.

Is there any other way to automate testing on real devices?

The easiest, cost-effective, and quickest way to test websites and mobile apps on a wide range of real devices are to avail services provided by various responsive testing tools. Some of the most popular and cost-effective, or even free testing platforms used by testers include Browserstack, Responsinator, Am I Responsive?, Screenfly, Google Resizer, XRespond, CrossBrowser Testing, etc.

UI tools

Now let us learn about different types of testing platforms that are well-designed to check UI responsiveness and performance.

1. Browserstack

The most favourite of every tester, Browserstack is one of the powerful and feature-rich UI testing tools with the ability to test more than 2000 real devices and browsers. Browserstack enjoys a very large customer base all over the world with Microsoft, Mastercard, AirBnB, and Twitter being the elite tech giants in the group. Needless to say, the desktop browser and mobile have 25,000+ renowned customers. From Windows to Mac, Android to iOS mobile devices, this intuitive cross-browser testing tool delivers a stunning User Experience for your web and mobile users.

Browserstack is SOC2 compliant and offers outstanding security features for both web and mobile apps. The incredible testing environment provided by these pristine browsers and mobile devices reduces the testing time, scale automation, and accelerates the speed of releases.

2. Responsinator

Responsinator is a free and handy UI testing tool developed by Tama Pugsley and Andy Hovey of the Batch Trading Company. It can be classified as one of the simplest, browser-based responsiveness testing tools available. If you are really excited to check how your app appears on different devices, just enter the URL of the site and see how the site appears on generic screens. Your site can be viewed both in vertical and horizontal layouts. Responsinator is at its best for performing quick checks. But when it comes to checking the breakpoints, its application is limited. Moreover, the extra cool User Interface and simplicity of Responsinator makes it a popular and well-liked responsive web design testing app.

3. Am I Responsive?

Similar to that of Responsinator, Am I Responsive? is an easy-to-use application UI responsiveness testing tool. Built to make testing more simple and fast, this tool just asks you to enter the URL of the application into the input field and Click GO!, the button placed adjacent to the field. Some of the attractions that prompt testers to choose this tool include:

• Take the screenshots of local web app development with a valid URL.

• Simply click & drag the devices displayed on the screen to rearrange and reorder them.

• Provision to test the responsiveness of web apps in your own browser is provided. What you need to do is to just drag and place the Am I Responsive Bookmarklet on your browser's bookmarks bar.

• Perfectly suitable for Apple devices as it can support almost every viewport size of iPhones.

• Take screenshots of all breakpoints; which is a point where the apps adapt to the specifications of each device to create an unbreaking or consistent user experience.

4. XRespond

The frequent resizing of the browser window is one of the tiring problems faced by testers. The process of testing the responsiveness of web apps by constantly gazing at one screen is straining as well as time-consuming.

XRespond is a well-designed open-source virtual lab where you can design, develop, and test websites. While using XRespond as a responsive testing tool, testers will be provided an environment where they could compare different views side-by-side like testing the website across entirely different devices or on multiple models of the same devices, say iPhone 8, 8 Plus, iPhone 7, iPhone 6, etc.

The most sought-after attraction of this tool is that we can determine how your website delivers UI experience across each device. In Short, we can conclude that XRespond is well-designed to build responsive web apps.

As in the case of Am I Responsive?, testers need to follow only 2 simple steps - Entering your website URL and Clicking the button. Your web app will get automatically displayed on various devices. XRespond also provides you with an option to choose and customize desired devices to test your website.

5. Screenfly

Screenfly is a free responsive testing tool. If you want an extra option to test various pixel measurements, then you can definitely go for Screenfly. Built to test your website's responsiveness on various screen sizes and different devices, Screenfly is one of the best emulators in the industry. As an easy to use responsiveness testing tool, you just need to type in your website address, select your list of devices and desired screen resolutions from the menu provided by the tool. You can also display your app in predefined resolutions.

The devices supported by Screenfly include desktop computers, mobile phones, tablets, and selected televisions. Mobile devices included by Screenfly are iOS, Android, and Blackberry. A wide range of tablets from Samsung, Motorola, Apple (iPad), etc. is also supported by Screenfly. Options are given to switch the screen display from landscape to portrait. You are also free to enable or disable the scrolling option.

6. Google Resizer

Google is undoubtedly the world's biggest tech giant and a key player in the field of digital technology. Google resizer is a prominent responsiveness testing tool that helps testers to check on various Material Design guidelines like breakpoints, responsive grids, surface behaviours, and user interface patterns, proposed by Google.

With Google Resizer, you can enter a custom URL so that you can view your app across all the Material Design breakpoints specified by Google. Google Resizer also has an option to view the demo of your app. What you want to do for seeing the demo is to select 'Pesto', 'Shine' from the drop-down list, which you get while clicking on the address bar. To make testing simple and easy for testers, the multi-device view offered by the screens is made interactive. The dimension resizing options for the desktop and mobile views are now possible with a simple click.

7. CrossBrowser Testing

Considered as one of the prominent rivals of Browser Stack, CrossBrowser Testing is one of a kind browser testing tool. CrossBrowser Testing platform can exclusively test on more than 1500 browsers - both desktop & mobile. To carry out automated tests, this tool can be used to run your site on real-world Android, iOS, and many other desktop browsers.

CrossBrowser Testing is an all-inclusive testing platform capable of:

• Making your test automation run in parallel

• Visually comparing screenshots

• Interacting & swiping with the site testing against the real-world devices and at the same time debugging the program code on the run

• Provision to take screenshots of a full page and the visible parts of a webpage or above the fold web page(without clicking or scrolling up/down)


As a significant aspect of modern web design strategy, every designer, developer, and tester must have in-depth expertise in the Responsive Web Design approach and various tools used to check the Responsiveness and performance of websites and mobile apps. Developers need to invest in longer development time in designing and developing RWD-based websites. It is equally challenging to test the responsiveness of a website, comparing to testing native apps. Only an expert and experienced team of QA/ Test engineers having the ability to test apps on various devices, platforms, browsers, and versions can successfully manage time and budget constraints associated with your project. If you build a responsive website, no matter the size of your business, you can convert your visitors into customers.