WhatsApp primarily uses Apple emoji images for emoji support on all platforms, including Android, Windows and the web. This differs from most apps which use the native emojis available for each platform.
The latest version of WhatsApp (2.16.278) uses emojis from Apple iOS 10 which include new gendered emojis, updated designs, and a rainbow flag emoji. This update is now available for WhatsApp Web, Android and Windows Phone.
A few emojis appear differently in WhatsApp to other platforms. The red heart emoji (offically known as heavy black heart) has a beating animation, and appears larger than the other emojis when sent in a WhatsApp message:
WhatsApp for Web, Android and Windows uses custom artwork for the middle finger emoji which was added in 2015 prior to Apple including this emoji.
Emojis from WhatsApp 2.16 are displayed below.