Understand the difference between template messages and free-form messages, and when to use each conversation type. See Telnyx guidance and requirements.
Two Categories of Messages
WhatsApp messages fall into two categories based on how conversations are initiated:
Template Messages (Business-Initiated)
Template messages are pre-approved message formats that you submit to Meta for review. They are required to start a new conversation with a customer or to message a customer outside the 24-hour conversation window.
Templates have three categories, each with different billing rates:
| Category | Use Cases | Examples |
| Marketing | Promotions, offers, updates | "Hi ##{{1}}, our spring sale starts tomorrow! Get 20% off with code SPRING20." |
| Utility | Transaction updates, alerts | "Your order ##{{1}} has shipped. Track it here: ##{{2}}" |
| Authentication | OTP, verification codes | "Your verification code is ##{{1}}. It expires in 10 minutes." |
Templates support variable substitution using ##{{1}}, ##{{2}}, etc. They can include headers (text, image, video, or document), body text, footers, and buttons (quick reply or call-to-action).
Free-form Messages (Session Messages)
Free-form messages can be sent only within a 24-hour window after the customer last messaged you. These create "Service" conversations and support rich content types:
- Text — Plain text up to 4,096 characters
- Image — JPEG, PNG (with optional caption up to 1,024 characters)
- Video — MP4 (with optional caption)
- Document — PDF, DOC, etc. (with optional caption and filename)
- Audio — OGG, MP3, etc.
- Sticker — WebP format
- Location — GPS coordinates with name and address
- Contacts — Contact cards (1–257 per message)
- Interactive — Quick reply buttons, CTA URL buttons, list messages
When to Use Which
| Scenario | Message Type |
| Customer hasn't messaged you yet | Template (required) |
| 24-hour window has expired | Template (required) |
| Customer messaged within last 24 hours | Free-form or Template (your choice) |
| Sending OTP or verification code | Authentication Template |
| Sending order update or receipt | Utility Template |
| Sending promotion or offer | Marketing Template |
| Responding to a customer's question | Free-form (within 24hr window) |