Can you give an advice on what tool to use for emulating different resolutions of smartphones?

[Anderson]

I need to test a web application on different popular mobile resolution. So I need a good simulation tool, because of lack of mobile devices
It's better if you can share a free tool, that you used previously and works correct, displaying web sites in different resolutions

[irl]

One free and widely-used tool for emulating different resolutions of smartphones is Google Chrome's DevTools. Here's how you can use it to test your web application on different mobile resolutions:

1. Open Google Chrome browser and go to the web application you want to test.
2. Open DevTools by right-clicking anywhere on the web page and selecting "Inspect".
3. In DevTools, click the "Toggle device toolbar" button (or press "Ctrl+Shift+M" on Windows or "Command+Shift+M" on Mac) to enable the device toolbar.
4. From the "Device" dropdown menu in the device toolbar, select "Edit" to customize the device settings.
5. In the device settings, you can specify the device type, resolution, and pixel density. You can also add custom device settings if needed.
6. Once you've set up the device settings, you can view the web application in the selected resolution by refreshing the page.

You can use DevTools to test your web application on various popular mobile resolutions such as iPhone X, Samsung Galaxy S9, Google Pixel 2, etc. DevTools also provides a responsive design mode that allows you to test your web application on different screen sizes and orientations.

In addition to DevTools, there are other free tools such as BrowserStack, Sauce Labs, and CrossBrowserTesting that allow you to test your web application on various mobile resolutions and devices. However, these tools may have limitations or require a paid subscription for full functionality.