Quick Answer: WhatsApp gives businesses 24 hours to freely message a customer after the customer messages first. After 24 hours, you can only send pre-approved template messages. This protects users from spam while allowing legitimate business communication.
You set up WhatsApp Business API. A customer messages you. You respond. They go quiet.
Three days later, you want to send them a follow-up. You type a message and hit send.
It fails.
Welcome to WhatsApp's 24-hour session window. Understanding this rule is essential for any business using WhatsApp API.
What Is the 24-Hour Window?
When a customer messages your business, WhatsApp opens a 24-hour "customer service window." During this window:
- You can send unlimited messages
- Any message format allowed (text, images, documents, interactive)
- No pre-approval required
- Messages are free or low-cost (service conversations)
After 24 hours of customer inactivity:
- Window closes
- Free-form messages blocked
- Only template messages allowed
- Higher per-message cost (utility/marketing rates)
Customer messages you at 2:00 PM Monday
│
▼
┌─────────────────────────────────────┐
│ 24-HOUR WINDOW OPEN │
│ Monday 2:00 PM - Tuesday 2:00 PM│
│ │
│ ✓ Send any message type │
│ ✓ Unlimited messages │
│ ✓ No template required │
└─────────────────────────────────────┘
│
▼ (24 hours pass with no customer message)
│
┌─────────────────────────────────────┐
│ WINDOW CLOSED │
│ │
│ ✗ Free-form messages blocked │
│ ✓ Template messages only │
└─────────────────────────────────────┘
Why This Rule Exists
Meta implemented the 24-hour rule to:
- Prevent spam: Businesses cannot bombard users with unsolicited messages
- Maintain trust: Users expect WhatsApp to be different from email/SMS spam
- Ensure relevance: Messages outside the window require explicit templates that Meta reviews
- Protect user experience: The core reason WhatsApp has 2+ billion users
Without this rule, WhatsApp would become another channel flooded with promotional messages. The restriction keeps it valuable for both users and businesses.
How the Window Resets
The 24-hour clock resets every time a customer sends you a message:
Monday 10:00 AM: Customer asks about pricing
→ Window open until Tuesday 10:00 AM
Monday 4:00 PM: Customer asks follow-up question
→ Window now open until Tuesday 4:00 PM (reset)
Tuesday 9:00 AM: Customer confirms order
→ Window now open until Wednesday 9:00 AM (reset)
Key insight: Keep customers engaged, and you maintain an open window indefinitely.
What Counts as Customer Activity
Resets the window:
- Customer sends text message
- Customer taps quick reply button
- Customer selects from list menu
- Customer sends image/document
- Customer shares location
Does NOT reset the window:
- Customer reads your message
- Customer views your status
- You send a message (only customer messages count)
Conversation Types and Pricing
WhatsApp categorizes conversations by who initiates and what content is sent:
| Conversation Type | Who Starts | Cost | Window Behavior |
|---|---|---|---|
| Service | Customer | Free (first 1,000/month) | Opens 24-hour window |
| Utility | Business (template) | Low | Opens new 24-hour window |
| Marketing | Business (template) | Higher | Opens new 24-hour window |
| Authentication | Business (template) | Low | Opens new 24-hour window |
Important: When you send a template message, it opens a new 24-hour window. This is how businesses re-engage customers.
Working Within the Window
Strategy 1: Maximize In-Window Engagement
Design conversations to keep customers responding:
Instead of:
Business: "Thanks for your order! It will arrive in 3-5 days."
[Customer reads and leaves - window expires]
Do this:
Business: "Thanks for your order! It will arrive in 3-5 days.
Would you like tracking updates via WhatsApp?
[Yes, send updates] [No thanks]"
[Customer taps button - window resets]
Strategy 2: End Conversations with Questions
Before the window closes, invite a response:
Business: "Your order has shipped! Tracking: DHL123456
Any questions about your delivery?"
Or use interactive elements:
Business: "Is there anything else I can help you with today?
[Ask another question] [That's all, thanks]"
Strategy 3: Use Templates Strategically
When you know a customer will need follow-up, send proactive templates:
Template: Order Shipped (Utility)
"Hi {{1}}, your order {{2}} has shipped!
Track at: {{3}}
Reply HELP if you have questions."
This opens a new window. If the customer replies "HELP" or any other message, you are back in free-form territory.
Outside the Window: Template Messages
When the window is closed, template messages are your only option. Plan ahead:
Essential Templates to Have Ready
| Use Case | Template Type | When to Send |
|---|---|---|
| Order confirmation | Utility | Immediately after purchase |
| Shipping update | Utility | When order ships |
| Delivery confirmation | Utility | When delivered |
| Appointment reminder | Utility | 24-48 hours before |
| Feedback request | Service | 1-3 days after delivery |
| Re-engagement | Marketing | 7-30 days inactive |
Template Message Flow
Window closed (72 hours since last customer message)
│
▼
Send template: "Hi Sarah, your order #123 has shipped!"
│
▼
Customer reads message
│
▼
Customer replies: "Great, when will it arrive?"
│
▼
NEW 24-HOUR WINDOW OPENS
│
▼
Free-form response: "It should arrive by Friday!
Here's the tracking link: ..."
Common Mistakes
Mistake 1: Waiting Too Long to Respond
Customer messages at 9 AM. You respond at 10 AM the next day.
Problem: Window already closed. Your response fails.
Solution: Respond within hours, not days. Set up automation for immediate acknowledgment.
Mistake 2: Sending Marketing Without Template
Window is open. You send: "Hey! We have a 20% sale today!"
Problem: This is marketing content sent as free-form message. Violates policy even within window.
Solution: Marketing messages should always use approved marketing templates, regardless of window status.
Mistake 3: Not Planning for Window Closure
Customer conversation ends. No follow-up templates prepared.
Problem: Three days later, you need to reach them. No approved template exists.
Solution: Create templates for common scenarios before you need them. Approval takes 24-48 hours.
Mistake 4: Over-Messaging Within Window
Window is open. You send 5 messages in 30 minutes.
Problem: Even within the window, aggressive messaging leads to blocks and reports.
Solution: Respect customer attention. One message at a time. Wait for responses.
Automation and the 24-Hour Window
AI Chatbot Best Practices
When using AI (like Oxaide) for WhatsApp:
Always respond immediately: AI ensures instant acknowledgment, maximizing window utilization.
Keep conversations interactive: AI can ask clarifying questions that keep customers engaged and windows open.
Escalate smartly: When AI cannot help, escalate to humans while window is still open.
Track window status: Your system should know when windows are closing to trigger follow-up logic.
Human Handoff Timing
Customer messages: 3:00 PM
AI responds: 3:00 PM (immediate)
Customer asks complex question: 3:05 PM
AI: "I'll have our team look into this. They'll respond shortly."
Window expires: 3:05 PM next day
Human available: 9:00 AM next day (6 hours remaining)
Human responds: 9:15 AM ✓ Still within window
If human was not available until afternoon, the window would close, and only a template could be sent.
Multi-Day Conversation Management
For complex sales or support spanning multiple days:
Day 1 (Window Opens)
Customer: "I'm interested in your services"
Business: [Detailed response with questions]
Customer: [Answers questions]
Business: "I'll prepare a proposal. Can I send it tomorrow?"
Customer: "Yes please" ← Window resets
Day 2 (Window Still Open)
Business: "Here's the proposal as promised..." ← Within window
Customer: "Thanks, I need to think about it"
Business: "Take your time! Any questions, just reply here."
← Window resets when customer replied
Day 4 (Window Closed)
Business sends template: "Hi {{name}}, following up on
the proposal I sent. Would you like to discuss any
questions? [Schedule call] [Ask question] [Not interested]"
← Opens new window
Customer: [Taps "Ask question"]
← New 24-hour window opens
Key Takeaways
- 24-hour window starts when customer messages you
- Window resets with each customer message
- Outside window, only template messages work
- Templates open new windows when customer responds
- Design for engagement to keep windows open
- Prepare templates before you need them
- Respond quickly to maximize window time
The 24-hour rule is not a limitation. It is a framework that keeps WhatsApp valuable for business communication. Work within it, and you have a powerful channel. Fight against it, and you will struggle.
For businesses wanting automated 24/7 responses that maximize every customer service window, explore Oxaide's WhatsApp AI solution.