Send WhatsApp broadcasts, manage templates, contacts, and conversations with Zernio API
Quick Reference
| Property | Value |
|---|---|
| Message types | Text, Template, Image, Video, Document, Audio |
| Template required | Yes (outside 24h conversation window) |
| Image formats | JPEG, PNG |
| Image max size | 5 MB |
| Video formats | MP4, 3GPP |
| Video max size | 16 MB |
| Document formats | PDF, DOC, DOCX, XLS, XLSX, PPT, PPTX, TXT |
| Document max size | 100 MB |
| Audio formats | MP3, OGG, AMR, AAC |
| Audio max size | 16 MB |
| Scheduling | No (use broadcasts with scheduling) |
| Inbox (DMs) | Yes |
| Inbox (Comments) | No |
| Group Chats | Yes, (Usage plan) (non-coexistence numbers only, see Group Chats) |
| Flows | Yes (interactive forms, surveys, booking) |
| Calling | Yes, (Usage plan) (inbound + outbound voice, see Calling) |
| Analytics | No |
Before You Start
WhatsApp requires a WhatsApp Business Account (WABA). This is different from a regular WhatsApp account.
Requirements:
- A Meta Business account (business.facebook.com)
- WhatsApp Business Account (created during the connection flow)
- At least one phone number registered with the WABA
- Approved message templates for initiating conversations (Meta reviews these)
- 24-hour rule: You can only send free-form messages within 24 hours of the customer's last message. Outside that window, you must use an approved template.
In This Section
Connection & Setup
Connect a WABA via redirect, headless credentials, or the dashboard
Broadcasts
Send template messages to many recipients with per-recipient variables
Templates
Create, list, and import Meta-approved templates
Contacts & Profile
Manage your contact list and business profile
Phone Numbers
Purchase, verify, KYC, and release numbers
Calling
Inbound and outbound WhatsApp voice calling
Group Chats
Create and manage groups, participants, and invite links
Inbox
Receive and reply to WhatsApp direct messages
Flows
Build interactive forms, surveys, and booking experiences
Click-to-WhatsApp Ads
Capture CTWA clicks and forward conversions to Meta
Pricing & Costs
What Zernio and Meta each charge
Media & Limits
Media requirements, analytics, and common errors
Related Endpoints
- Broadcasts - Create and send WhatsApp broadcast campaigns
- Contacts - Manage your WhatsApp contact list
- Templates - Manage Meta-approved WhatsApp templates
- Group Chats - Create and manage WhatsApp group conversations
- Flows - Build interactive forms, surveys, and booking experiences
- Connect via Credentials - Headless WhatsApp connection
- Inbox - View and manage WhatsApp DM conversations (included with the Usage plan)