# A2P SMS This documentation provides a comprehensive guide to integrating with our A2P (Application-to-Person) SMS API, designed for businesses and developers looking to send high-volume, automated text messages to mobile users. Whether you’re sending OTPs, transactional alerts, promotional campaigns, or notifications, our robust and scalable API ensures fast, secure, and reliable message delivery across local and international networks. Learn how to authenticate, structure your requests, handle delivery reports (DLRs), manage sender IDs, and troubleshoot effectively. With support for HTTP/S protocols and flexible parameter configurations, our A2P SMS API gives you full control over your messaging workflows. --- # Agent Instructions: 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: ``` GET https://developer.9bits.net/messaging/a2p-sms.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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.