> For the complete documentation index, see [llms.txt](https://docs.bird.com/applications/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bird.com/applications/channels/channels/supported-channels/whatsapp/concepts/faqs.md). # FAQs ### Can I send bulk messages on WhatsApp? Yes, you can use [Approved message template](/applications/content/message-templates/concepts/whatsapp-message-templates.md#approved-template) to send WhatsApp messages in bulk to a predefined audience via Campaigns. ### Do customers need to opt-in to receive WhatsApp messages from my business? Yes, if you want to initiate a conversation with your customers by sending them an [Approved message template](/applications/content/message-templates/concepts/whatsapp-message-templates.md#approved-template). Before you can contact them, your customers need to have shared their mobile phone number with your business and opted in to receive messages. However, customers are free to initiate conversations with you without having opted in previously. ### How do I send a WhatsApp message to a customer? If you’re sending a message to a customer to initiate a conversation, you’ll need to use a message template. You’ll also need to do this if you’re replying to a customer after the 24-hour care window has closed. ### What is the WhatsApp customer service window? The customer service window is a period of time during which a business can send any type of message to a recipient (user). This window lasts for 24 hours and it can be initiated by either the business or by the customer. ### How does the customer service window work? The window starts when a customer sends a message and the business replies. This is known as user-initiated conversation and no prior opt-in is required. When a business sends a template message to a recipient (user), then the customer service window starts. This is known as a business-initiated conversation and prior opt-in is required. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.bird.com/applications/channels/channels/supported-channels/whatsapp/concepts/faqs.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.