How to sign in to WhatsApp Web from an iPhone Otherwise, once you've logged in with your web browser, you can chat away even when your phone's battery is dead or it's offline. This could be a problem if you want to access WhatsApp Web from a new computer and your phone is dead. Since your WhatsApp profile is tied entirely to your phone number, there's no username or password you can use to log in directly instead, you need to authenticate WhatsApp Web through its mobile apps. There's one small catch in that you'll still need to use WhatsApp on your iPhone or Android smartphone to link up those devices to your account. Thankfully, WhatsApp added a multi-device feature two years ago that lets you link up to three other devices directly to your account. At one time, WhatsApp needed to be running on your smartphone to relay messages between WhatsApp's servers and the browser-based version of the app. What's more, you can now use WhatsApp Web even when your phone is offline. WhatsApp Web is a great way to keep in touch with friends, family, and colleagues when you don't have your smartphone handy or you'd simply rather not type out messages on a smaller touchscreen keyboard. Latest version of Chrome, Firefox, Microsoft Edge, Opera, or Safari
