The main difference between WhatsApp and SMS messages is that WhatsApp messages are sent over an internet connection instead of through a cellular network. This means that they are usually faster and more reliable. Additionally, WhatsApp messages usually offer more features such as the ability to send multimedia (e.g. images and videos) as well as audio and document files. Finally, WhatsApp messages allow one-to-one and one-to-many messaging where SMS messages are only for one-to-one conversations.