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In an era of instant messengers and AI chatbots, Short Message Service (SMS) remains the only universal protocol capable of reaching every mobile device on Earth without an internet connection. It is the backbone of global security (2FA), critical alerts, and business continuity.
Understanding the underlying mechanicsÔÇöfrom SS7 signaling to A2P routingÔÇöis no longer just for telecom engineers. Developers and businesses must master these protocols to ensure deliverability, compliance with 10DLC regulations, and protection against fraud like smishing.
From protocol fundamentals to advanced campaign optimization — deep dives into mobile messaging.
Start here. Understand the SS7 signaling architecture, the history starting from 1992, and why SMS remains the most reliable communication channel on Earth.
Master high-ROI campaigns. Learn about timing, segmentation, and critical TCPA compliance to avoid fines.
A technical deep dive into how SMS works without data or Wi-Fi using the cellular control channel.
Why one emoji costs double. Learn encoding rules to reduce segment counts and save campaign budget.
SMS (Short Message Service) is more than just texting. It's the universal protocol that powers 2FA, emergency alerts, and business communication globally.
Read Full HistoryUnlike instant messaging apps that rely on IP networks, SMS utilizes the SS7 (Signaling System No. 7) protocol. This allows messages to be transmitted via the control channel of the cellular network, ensuring delivery even when mobile data is unavailable. This reliability makes it the standard for critical notifications.
The ecosystem is divided into Person-to-Person (P2P) and Application-to-Person (A2P) traffic. A2P is strictly regulated (requiring 10DLC or Short Codes) to prevent spam, while P2P is standard conversational traffic. Understanding this distinction is vital for compliance with carriers.
SMS character limits are dictated by encoding. Standard messages use GSM-7 (160 characters). However, introducing a single emoji or non-Latin character forces the message into Unicode (UCS-2), reducing the limit to 70 characters per segment, effectively doubling costs for businesses.
While SMS remains dominant, RCS (Rich Communication Services) is the next evolution, offering high-res media, read receipts, and typing indicators native to the OS, bridging the gap between SMS and apps like WhatsApp.
Calculate segments, detect encoding type, and optimize your messages before sending. Essential for planning bulk SMS campaigns.
Direct answers to the most searched questions about SMS technology, device compatibility, and marketing.
On iPhone, green bubbles indicate SMS sent over cellular networks to non-Apple devices. Blue bubbles are iMessages sent over the internet. On Android, SMS is the default standard.
READ_COMPARISONSMS marketing involves businesses sending promotional campaigns to opted-in customers. It boasts a 98% open rate. Key examples include flash sale alerts and appointment reminders.
VIEW_STRATEGIESSMS supports text only up to 160 characters. MMS allows for pictures, video, and longer text (1,600+ chars), but requires a data connection and costs more to send.
COMPARE_PROTOCOLSAn SMS notification is an automated message triggered by a specific event. Common uses include One-Time Passwords (OTP) and delivery updates. These are transactional messages.
LEARN_MORE
Learn what 10DLC is, why registration is required for business texting in the US, and how it compares to short codes.
Understand the difference between SMS and iMessage. Learn why some messages are blue and others green, plus data usage, features, and cross-platform tips.
Learn what bulk SMS is, why businesses use mass text messaging, and how to launch successful campaigns. Includes pricing, providers, and compliance tips.
Common questions about SMS technology and marketing.
Yes. SMS (Short Message Service) is a protocol that uses cellular signaling channels (SS7) and does not require an internet connection. iMessage (blue bubbles) and WhatsApp are "Over-the-Top" (OTT) applications that send data over the internet (Wi-Fi or mobile data).
A standard SMS is limited to 160 characters when using the GSM-7 character set. However, if you include a single emoji or special character (like Chinese or Arabic scripts), the message encoding switches to Unicode (UCS-2), reducing the limit to 70 characters per segment. Messages longer than these limits are split into segments.
No. SMS works entirely over the cellular voice network (specifically the signaling channel). This makes it more reliable than internet-based apps in rural areas, basements, or during emergencies where data networks might be congested or unavailable.
An SMS API (Application Programming Interface) allows developers to integrate SMS capabilities into software applications. It is commonly used for sending automated notifications (like shipping updates), One-Time Passwords (2FA), and marketing campaigns directly from code, without needing a physical phone.
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