# whatsapp

- [What is the difference between whatsapp.failed and whatsapp.rejected?](/explained/whatsapp/whatsapp-failed-vs-whatsapp-rejected)
- [What is WhatsApp opt-in?](/explained/whatsapp/what-is-whatsapp-opt-in)
- [WhatsApp Business app vs API: which do I need?](/explained/whatsapp/whatsapp-business-app-vs-api-which-do-i-need)
- [Why was my WhatsApp template rejected?](/explained/whatsapp/why-was-my-whatsapp-template-rejected)