Template messages and the 24-hour window, explained
This is the rule that surprises businesses most often, usually the first time they try to follow up on something and find they cannot. It is worth understanding before you design any process that depends on reaching people.
The customer opens the door
When a customer messages you, a service window opens. Inside it you can reply freely, in your own words, as many times as the conversation needs.
When that window closes, free-form messaging stops. You cannot simply send a follow-up whenever you like. This is deliberate: it is the mechanism that stops the Platform filling with unsolicited business messages.
Outside the window you need a template
A template is a message you write in advance and submit to Meta for approval, with placeholders for the details that vary, such as a name or an order number.
Approved templates are what let you reach someone after the window has closed. They are how renewal reminders, delivery notifications and appointment reminders actually work.
Templates are categorised by purpose, and the category affects both how they are reviewed and how the resulting conversation is priced.
Getting templates approved
Write the specific message you actually intend to send. Vague templates that look like they could carry anything tend to be rejected, and so do ones that read as marketing while being submitted as something else.
Put the variable parts in placeholders rather than writing a template per customer, and keep the wording plain. Meta is checking that the recipient will recognise why they are hearing from you.
Designing around it
Do the work while the window is open. If a customer has just asked about a renewal, that is the moment to complete it, not tomorrow.
Where a delay is unavoidable, know in advance which template will carry the follow-up and get it approved before you need it. Discovering the rule at the moment you need to reach someone is the expensive way to learn it.
This guide describes Meta's own rules, which change and differ by country. Check Meta's current documentation before relying on any specific figure or timeline.