WhatsApp templates explained: categories and the 24-hour window

Your accounts clerk cannot sit at a desk, type a reminder about invoice 4471 and press send to a dealer who has been silent for a full day. Not on the API. The platform refuses free text outside the window and asks for an approved template instead.

The rule protects people from unwanted business messages. Meta reviews every opening message, whether it comes from a clinic, a showroom or an online brand, before it reaches a phone. That review is the approval you wait for.

An approved template is a fixed body with numbered gaps. The gaps hold the customer name, invoice number and due date, which your billing system fills in at the moment of sending, one value per gap and per recipient. The wording around them never changes.

The window opens when a customer messages you. It stays open for 24 hours from their latest message, and every new message from them restarts the clock, so a busy chat can run for days.

While it is open, your agent or chatbot can answer in plain text, send a photo of a bent bracket or attach a PDF. Nobody approves any of it. This is the part that feels like ordinary chat.

Once the window closes, your side of the thread goes quiet. A dispatch update at nine in the evening for a parcel booked the previous morning is the classic case, and a free-text message would simply fail to send. It needs a template.

Utility templates serve a transaction the customer already started. Order confirmations, dispatch updates, appointment reminders, payment receipts and delivery slot changes all belong here, because each one carries facts about something that already exists.

Marketing templates promote. A festival offer, a new arrival, a service camp invitation or a winback note all count, and Meta can reclassify a utility draft as marketing if the wording sells.

Authentication templates deliver one-time passcodes for login or a delivery handover. The layout is strict. Each category is billed and monitored on its own terms, so the label you pick carries real consequences for cost and for how Meta judges your number.

A variable is a numbered placeholder written with double curly braces. The first might hold a name and the second an amount, and your system swaps in real values for each recipient just before the message goes out.

Reviewers read it filled in. A template that reads fine with a short name but collapses under a long list of products, or that places two variables side by side, gets sent back. Keep it natural.

Keep each gap short and predictable. Long or messy data, such as a table of line items with quantities and tax columns, belongs in an attached PDF rather than inside a variable.

Draw every flow with the window in mind. A reminder flow begins with a template because the customer is silent, and if they reply, the window opens and your team can switch to free text.

Add a button to the template, such as Pay now or Reschedule. A tap counts as a reply. The window opens, and every later step can be a plain message, which removes a surprising amount of template writing from the project.

Your next step is a list. Write down every message your business sends today, mark each as first contact or reply, and tag its category. Then write templates only for the first contact ones.