WhatsApp and artificial intelligence
Service message
A service message is any non-template message a business sends through the WhatsApp Business Platform within the 24-hour window that a person opens by writing in: text, photos, audio, buttons. It needs no prior approval, and Meta charges for it in a category of its own.
Also known assession message · non-template reply · customer service message
When it can be sent
The 24-hour window rules: while it is open, the business replies with whatever it needs without going through Meta first; once it closes, it can only write with an approved template, which belongs to its template category. Meta calls a service message any non-template message that does not come from its own AI agent (Meta Business Agent), whether it is written by a member of staff or by a third party's assistant.
What has changed is how it is charged. Meta has billed per delivered message since 1 July 2025, and service messages stopped being charged on 1 November 2024. From 1 October 2026 it charges for them again beyond a monthly allowance per number, which does not carry over from one month to the next, and it also charges for utility templates sent while the window is open. If the Messaging account has no payment method, Meta stops delivering service messages as soon as the allowance runs out.
Worth knowing
What people take for granted: that replying to a resident costs nothing because they wrote first. That was true between November 2024 and September 2026; since October it depends on how many service messages leave that number in the month. In a residence with lots of questions, it is worth checking that the account has a payment method before the allowance runs out. What each item weighs: how much a WhatsApp chatbot costs.
Sources
Related terms
- 24-hour windowThe 24-hour window, or customer service window, is the period that opens every time someone messages a WhatsApp Business Platform number: for 24 hours from their last message you can reply freely; once it closes, you can only write to them with an approved template.
- Template categoryThe template category is the class Meta assigns each WhatsApp message template to: marketing, utility or authentication. It decides what content the template may carry and what Meta charges for each message sent. Whoever creates the template proposes it, Meta validates it on approval and can change it later.