Why are Sirena’s sessions used?

The WhatsApp Business API service brings countless benefits to businesses. Among them, the main one, is that the API allows several users to use the same WhatsApp line.

When you use Sirena you are using the official WhatsApp API. As the API is commonly used by companies that can generate thousands of interactions, WhatsApp placed certain rules to prevent misuse of the application.

One of those rules is that to start a session you must use message templates pre-approved by WhatsApp,which generate a cost when sent.

To structure this rule, WhatsApp created the concept of "Session". As this is a WhatsApp rule, everyone who is authorized to use the API, including our competitors, charges for sending the templates needed to log in.

What is a "Session" for WhatsApp?

It is a 24-hour period that opens with a message received from the customer or a message template sent by the company. Each session starts counting from the moment the first message is sent, regardless of whether the interaction was initiated by the company or the customer.

The charge, therefore, will not be made for each message template sent, but for the session that corresponds to the 24-hour period, which means that as many messages as your company needs can be sent, including message templates, whenever the mentioned period is respected.

Even for companies that send message templates frequently, if within the 24-hour period, only a charge will be made for the beginning of the session.

After the 24-hour period, the session ends and it will automatically reopen when you send a message template or receive a new message from your customer. This new message causes a new session to start, which will generate a new charge.

If this new message is sent by the customer or by the company within 24 hours of the last message from the customer, it will be considered as a login by your customer and not by your company and it will not be necessary for this message to be a model of message. This scenario represents what we call an "extended window".

On the other hand, if this new message is sent after 24 hours of the last message from the customer, that login will be charged as initiated by the company and it will be necessary to use a message template.

It is important to make it clear that the charge is not made by message, but by login.


In the pricing section of our website, you will be able to see the costs of these templates.

For each country there is a variable cost to start a session. This cost depends on the country in which your company has a legal presence, according to what you reported when you subscribed to Sirena.

In the case of this particular country, the price per session initiated by the customer is 0.022 USD, while if you start it with a template it will more than double, 0.037 USD.

That is, to avoid spam, WhatsApp sets a higher cost for templates started by your company.

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