Whatsapp web in iPad mini

As said its generally not supported on an iPad, however as ShagCA points out above, requesting the desktop site on Whatsapp, will let you access Whatsapp Web on your iPad. Be aware that functionality may not be 100% since its technically not really supported on an iPad.

To request the desktop site, press and hold on the "refresh" icon on the right side of the address bar, and then tap on "Request Desktop site" in the menu that appears.

No. Whatsapp cannot be used on an iPad at all even through the website. Why this is, only the Whatsapp developers know this. Apple has nothing to do with whatsapp or its developers.

Contact them to find out why:

Contact WhatsApp

Try clearing Safari (Settings - Safari - Clear history and website data). Then go back to Safari and retry accessing the site. Don't forget to request desktop site.

Can you tell us what the problem is? Launch Safari browser and type web.whatsapp.com. You may have to request desktop version of the web page. I could certainly connect to Whatsapp web on my iPad Air last year. If they start blocking tablet browsers today, that's something new.

There are so many complaints regarding the Whatsapp app it's no wonder you are having problems but what you can do is contact the app developer > Contact a third-party vendor - Apple Support