Alibaba Cloud Short Message Service (SMS) is a cloud-based messaging platform that enables enterprises to send SMS messages to customers in over 200 countries and regions. The service supports three primary message types: one-time password (OTP) messages, notification messages, and promotional messages. The platform provides API operations for programmatic message sending, supporting Java, PHP, Python, Node.js, and C# programming languages. Users can send messages to up to 1,000 phone numbers in a single API request. The service includes intelligent routing that selects optimal delivery paths based on throughput and delivery success rates in real time. SMS includes message scheduling capabilities and quality of service (QoS) prioritization, ensuring high-priority messages like OTPs are delivered before promotional content. The platform supports message variables and dynamic content for customization based on user profiles. Security features include identity authentication for both Alibaba Cloud accounts and Resource Access Management (RAM) users to control API access. The service provides controllable message sending with configurable limits on daily message volumes per customer and total messages sent to prevent resource overconsumption. The platform offers message analysis capabilities, allowing users to view metrics such as request counts, sent messages, failed messages, and resource plan usage. It supports super-long messages by dividing content exceeding 140 bytes into multiple segments that are reassembled at the terminal. Asynchronous notifications are sent to callback URLs when backend tasks complete.