SMS has been around since the 1990s, and its greatest strength is its immense reliability. With its universal reach, SMS works on all mobile phones in the world, including older feature phones.
Many other messaging services require an internet connection. SMS is sent over the standard mobile network (2G/3G/4G/5G) and works even if you lack mobile data or Wi-Fi. This ensures reliable delivery for critical messages, which is why banks, government agencies, and other essential services still use SMS for things like one-time codes (2FA) or other important information.
See the comparison in "SMS vs. RCS”
SMS stands for Short Message Service.
SMS was designed to be sent via the existing mobile network's control channels (the signals that phones and cell towers use to communicate with each other regarding coverage, incoming calls, etc.). Because the space in these channels was strictly limited, a maximum limit of 140 bytes was set, which corresponds to exactly 160 characters (using the standard GSM 7-bit alphabet).
SMS is best suited for situations where guaranteed delivery, immediate attention, and universal reach are more important than polished design. Here are examples of applications where SMS remains completely superior:
1. Security and verification (2FA / OTP)
SMS is the world's most widely used channel for two-factor authentication (2FA) and one-time passwords (OTP). The reason is that it requires no app installation, works for all ages and devices, and is delivered in seconds.
2. Critical public alerts and notifications
When information must reach 100% of the population without delay, there is no real alternative to SMS. For example: public safety alerts, crisis information from municipalities, service disruptions (e.g., power outages or water leaks), and emergency alerts to on-call staff. The reason is that it does not require the user to have mobile data enabled, Wi-Fi, or a specific app installed. Furthermore, SMS gets through even when mobile networks are heavily congested.
3. Important reminders and appointments
Essential reminders where a missed appointment costs money or creates administrative problems. For example: dental and doctor appointments, vehicle inspections, delivery notifications (e.g., "Your package is ready for pickup"), and restaurant table notifications. The reason is that SMS has an open rate of around 98% (compared to email's ~20%), and most people read the message within 3 minutes.
4. B2C transactions and "last-minute" notices
Targeted communication at the moment of purchase or when something requires quick action from the customer. For example: door codes for hotels/rental cars, ticket links for concerts/trains, exclusive last-minute offers, or reminders about unpaid invoices before debt collection. The reason is that SMS does not end up in spam filters or "promotions tabs" like email often does, but appears directly on the mobile device.
5. Municipal and internal corporate communication
When you need to reach staff or citizens who are not sitting in front of a computer all day. For example: calling in extra staff in healthcare/schools, quick shift changes, and messages from schools/preschools to parents. This makes it perfect for "field workers," shift workers, or target groups who do not have their own email address within the organization.
