The per-conversation model explained
Meta charges per conversation, not per message. A conversation is a set of messages between your business and a contact, opened by a single event and valid for 24 hours. All messages exchanged in those 24 hours count as a single conversation.
There are two conversation types: Business-Initiated (your business sends first) and User-Initiated (the customer sends first). Prices differ, with User-Initiated generally costing less.
Country and category rates
Prices vary significantly by country. Developed markets (Western Europe, North America) have higher rates than emerging markets. Exact rates are published by Meta on the official pricing page and updated periodically.
User-Initiated conversations often have a reduced or zero price in some markets. Encouraging clients to contact you first, when possible, reduces total costs.
How a new conversation window opens
A new conversation (and its cost) opens in four situations: first message to a contact, message to a contact with no interaction in the last 24 hours, template category change from previous conversation, and response after the 24-hour window expired.
How to optimize costs with the per-conversation model
First optimization: use open conversation windows. If a client wrote in the last 24 hours and the window is still open, you can send additional messages at no extra cost.
Second optimization: correct template categorization. Each Utility template sent as Marketing pays the higher Marketing rate. Review all your templates with Chat API support.
Third optimization: volume. Negotiate discounted rates with the BSP provider for high monthly volumes.
