# Cost Meta charges for WhatsApp API usage based on sessions. A session is said to have started, when a user sends a message to your WhatsApp number, or the business initiates a chat with the user by sending a template message. Business-initiated conversations have three categories `utility`, `authentication`, and `marketing`. User-initiated is categorized as a `service conversation`, each with different rates:
MarketingBusiness-initiated conversations with customers that have opted into, which may include promotions or offers, informational updates like a back-in-stock alert, or invitations for customers to respond or take action. A marketing conversation is any conversation that does not qualify as utility or authentication.
UtilityBusiness-initiated conversations with customers that have opted into facilitating a specific, agreed-upon request or transaction, or update to a customer about an ongoing transaction, including post-purchase notifications and recurring billing statements.
AuthenticationBusiness-initiated conversations with customers that have opted into, enabling businesses to authenticate users with one-time passcodes (OTP), potentially at multiple steps in the login process (e.g., account verification, account recovery).
ServiceAny user-initiated conversation, such as to resolve a customer enquiry.
The conversation starts when the first business message in a conversation is delivered. However, the conversation type will be defined once a message has been sent by the business with the category of the template message used. {% hint style="success" %} By default, every WhatsApp API gets 1,000 free sessions each month. {% endhint %} ## Cost per session Cost varies based on the country and type of session being used. {% embed url="" %}