The short answer
When a customer messages your business number on the WhatsApp Business Platform, you can reply with free-form messages for 24 hours after their most recent message. This is the customer service window. Outside it, a business can only start or restart a conversation with a message template that Meta has approved in advance. For a CA firm, that means the first request of a filing cycle and most later reminders go out as templates.
How the 24-hour window works
The clock starts when the client sends a message and restarts every time they send another. While it is open, your replies can be ordinary text, including questions, acknowledgements and follow-ups. When it closes, free-form messages stop being delivered until the client writes again.
The rule exists to keep businesses from sending unsolicited messages at will. It is a platform rule, not something a software vendor can turn off.
What a message template is
A template is a message whose wording is submitted to Meta for approval before use. It can include variables, such as the client's name, the month and the list of documents. Templates are reviewed and assigned a category, and poorly written or misused templates can be rejected or can hurt the number's quality rating.
A good document-request template is short, specific and courteous. It says who is writing, for which month, and exactly what is needed.
What this means for a filing cycle
- Kickoff, 7 days before the due date. The client has not written recently, so the window is closed. The request goes out as a template.
- The client replies with a photo. The window opens, and the firm can acknowledge the file and ask follow-up questions as normal messages.
- Silence for a few days. The window closes again. The next reminder goes out as a template.
- The list is complete. Reminders stop.
The practical lesson is to treat every business-initiated message as a template and to write each one carefully.
Writing templates that get answered
- Name the month and the documents. "Purchase invoices for August 2026" beats "documents".
- Keep it to a few lines. Clients read on a phone between other things.
- Say what a reply looks like: "a photo or PDF on this chat is enough".
- Do not sound like a warning. Polite reminders are answered; threats are muted.
- Avoid sending anything that reads like marketing in a utility message. Keep requests about the client's own documents.
Consent and opting out
Businesses need the recipient's permission to message them on WhatsApp, and every client should be able to stop. A simple convention is to accept a STOP reply at any time and honour it immediately. Fyliio supports a STOP opt-out for clients.
Messaging limits and planning your start
Business numbers have limits on how many new conversations they can start each day. The limits generally begin modestly and grow as the number builds a good quality record. A firm with hundreds of clients should plan when it opens each cycle rather than messaging everyone in one burst, and should not buy a new number in a hurry to get around a limit.
How Fyliio handles the mechanics
Fyliio uses approved templates to start conversations, saves every inbound message before processing it so none are lost, checks that each webhook is genuinely from Meta, and downloads files before WhatsApp's media links expire. Reminders pause for 12 hours whenever a client replies, and quiet hours run from 21:00 to 09:00 IST. Staff open each cycle; Fyliio sends the requests and reminders on schedule from there.
See how the platform works and the nudge rules that do not annoy clients.
Frequently asked questions
Can I send a free-form reminder after 24 hours of silence?
No. Once the window has closed, a business-initiated message has to be an approved template.
Does a client reply reopen the window?
Yes. Any message from the client starts a fresh 24-hour window.
Do my clients need WhatsApp Business?
No. Clients use ordinary WhatsApp. The business side uses the WhatsApp Business Platform, which is separate from the WhatsApp Business app.
Is this the same as the WhatsApp Business app on a phone?
No. The Business Platform is the API used by software such as Fyliio. Its rules about windows and templates differ from the app's.
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