Short message service (SMS)
Short Message Service (SMS) is a communication protocol that allows short text messages—typically up to 160 characters—to be sent between mobile devices. Despite being decades old, SMS remains one of the most reliable and widely used messaging channels in the world. It works on nearly every mobile phone, does not require an internet connection, and is often used for time-sensitive or critical notifications.
In AI-based customer service, SMS is commonly used to reach customers quickly and continue conversations outside traditional web or app experiences.
How does short message service work?
SMS messages are sent through cellular networks using signaling channels rather than data connections. When a message is sent, it passes through a Short Message Service Center (SMSC), which routes it to the recipient’s carrier and device. If the recipient is unavailable, the SMSC stores the message and retries delivery.
SMS relies on carrier infrastructure, making it highly resilient. This is why businesses often use it for authentication codes, delivery updates, and service notifications.
The power of SMS in AI-driven customer interactions
SMS is especially valuable for AI-based customer service because it meets customers where they already are: their phones. Agentic AI can use SMS to send proactive updates, confirm customer actions, follow up on unresolved issues, request additional information, and notify customers of important changes or next steps.
SMS also supports accessibility and inclusivity. Customers don’t need to install an app or log in to a portal. This makes SMS an effective fallback channel when other systems fail or when users prefer simplicity. When combined with omnichannel customer support, SMS helps create seamless customer journeys across platforms.
SMS will increasingly act as a lightweight control channel rather than a full conversation surface as customer engagement becomes more automated. AI systems will use SMS for confirmations, status checks, and handoffs between channels, triggering richer interactions in chat or voice when needed. Greater emphasis on consent, timing, and message relevance will help maintain trust while preserving SMS’s immediacy and reach.
Common SMS use cases for AI agents
AI-driven systems frequently use SMS in scenarios where speed and visibility are critical. Common examples include:
- Appointment reminders and confirmations
- Order and delivery status updates
- One-time passcodes or verification messages
- Two-way customer support conversations
- Service outage or emergency notifications
These use cases benefit from SMS’s immediacy, broad device compatibility, and consistently high open rates, making it especially effective for time-sensitive communication.
Trade-offs and limitations to consider
While SMS is reliable, it has limitations that matter in AI-based systems, particularly as interactions grow more complex or sensitive:
- Limited message length, which restricts complex explanations
- Lack of rich media, compared to chat apps or web messaging
- Security considerations, since SMS is not encrypted end-to-end
- Cost at scale, especially for international messaging
Within sensitive workflows, SMS is often paired with stronger verification systems, limited to notification-only use cases, combined with other communication channels, and supported by clear escalation paths to human agents. This helps reduce the risk of misinterpretation or incorrect AI-driven instructions.
