What is the WhatsApp service window?
The time-bounded customer-service period that begins or refreshes when a user messages a business and affects which message types can be sent without an approved template.
Why is this important?
The window shapes handoff, automation, follow-up, and cost behavior. Ignoring it causes rejected sends and broken customer journeys.
How it works
Inbound user messages create or extend the period. Systems track the last qualifying message and choose free-form replies or approved templates under current policy.
Technical example
A support agent sends a troubleshooting reply inside the window. After it closes, re-engagement may require an approved utility or marketing template.
Implementation notes
Store timestamps consistently, account for webhook delay, do not guess eligibility, and verify current window and pricing rules because policy changes.
