How Meta’s 24-hour customer service window works on Cloud API, when you need a template, and how Nautilus Flow handles session vs template sends.
The WhatsApp customer service window is a Meta Cloud API rule, not a Nautilus Flow setting. After a customer messages your business, you may send free-form replies for 24 hours. Outside that window, the first business-initiated message must be a Meta-approved template.
This is the rule agencies and ecommerce teams hit when a Click-to-WhatsApp lead goes quiet, or when an order update needs to go out two days later.
When a user sends you a message (including tapping a Click-to-WhatsApp ad or a WhatsApp button), Meta opens a 24-hour session on that conversation. During the session you can send:
When the session expires, free-form send is rejected until the customer writes again or you send an approved template that re-opens a new window after they reply.
Meta documents the window under Cloud API messaging. Treat their policy as source of truth; Nautilus Flow enforces it on send so you do not burn a quality-rated number on illegal free-form traffic.
Templates are classified by Meta (authentication, utility, marketing). Category, quality, and conversation pricing are billed by Meta, not as part of the Nautilus subscription.
The inbox shows whether the conversation is still in session so agents do not guess. Campaigns and automations that fire after checkout, shipping, or a delay use the templates you mapped in the workspace. If Meta would reject a free-form send, we do not send it as text and hope.
For store events, pair this with the Shopify or WooCommerce integration so order templates are utility messages tied to a real checkout—not a broadcast disguised as support.