Facebook-owned WhatsApp is working on bringing the dark theme support on the WhatsApp web. The dark theme is already available on the WhatsApp Android and iOS apps. The dark theme for WhatsApp web is still in the development phase, and the feature is not yet available to end-users. However, you can enable the dark mode on the WhatsApp web right now.
To enable the dark mode on WhatsApp web, open web.whatsapp.com from any browser and then scan the code via WhatsApp app to log in. After that, right-click on the window and click on Inspect. Alternatively, you use keyboard shortcut Ctrl+Shift+I to open the inspect window. Once the inspect window is open, you will see codes on the page, make sure you are on the Elements tab. If you are not, then select the Elements tab and search for the string- “body class = web”. Double click to edit and replace “web” with “web dark”. The dark theme will be enabled as soon as you press enter.
This method works on all modern web browsers. Since these changes are temporary, WhatsApp web reverts to the default (light) theme when you refresh the page or open the WhatsApp web again. You will have to perform the same steps again to get the dark theme.