The 24-hour window
If you read one page in this manual, make it this one. Almost every "why can't I…" question traces back to this single rule.
The rule
WhatsApp does not let businesses message people whenever they feel like it. Instead:
- A customer messages you. A 24-hour window opens.
- Inside those 24 hours, you can reply with anything — plain text, images, documents, voice notes. No approval, no template.
- When the window closes, you can no longer type freely. To reach that person again you must send an approved template, which opens a fresh window if they reply.
The clock restarts every time the customer sends a new message. An active back-and-forth conversation never closes.
It is 24 hours from their message, not yours
Replying does not extend the window. Only a new message from the customer does.
What this means in practice
| You want to | Inside the window | Outside the window |
|---|---|---|
| Answer a question | Just type it | Send a template first |
| Send a photo of a product | Attach and send | Send a template with an image header |
| Follow up on an old enquiry | — | Template only |
| Send an offer to your list | — | Marketing template, to opted-in contacts |
So: you never need a template to reply to someone who just messaged you, and you always need one to start a conversation.
Why it costs what it costs
This is also the rule behind Wap2b's pricing.
- Replies inside an open window are free. You are charged nothing for them, however many you send.
- Starting a conversation costs money, because Meta charges for it. The price depends on the template's category and the country you are messaging.
- Each message the customer sends you is charged, at a small flat rate — much less than a template, but not nothing.
That is why a business that mostly answers customers spends very little, and a business that mostly broadcasts spends more. Full detail in How pricing works.
How to tell where you stand
Open Chatbox. A conversation whose window is still open lets you type. One whose window has closed offers you a template instead — Wap2b will not let you send something WhatsApp is going to reject.
Making the window work for you
- Answer quickly. A window that closes because nobody replied for a day costs you a paid template to reopen.
- Give people reasons to message first. A click-to-chat link, a QR code on your packaging or a website chat button all mean the customer opens the conversation — which costs a fraction of a template and starts a window you can answer in for nothing. See Getting customers to message you.
- Do not stockpile replies. If you have something to say and the window is open, say it now.
If something goes wrong
- "You can only send a template to this contact". The window has closed. Pick a template, or wait for them to message again.
- You replied and it failed. The window probably closed between the conversation loading and you hitting send. Reload the conversation.
- A customer says they never got your reply. Check Message logs for the actual status — see A message failed.