How group texting works, from your phone to theirs

SMS, MMS, and RCS: what is the difference?

SMS (Short Message Service) is the original text message standard, limited to 160 characters of plain text and supported on every mobile phone. MMS (Multimedia Messaging Service) extends SMS to support images, audio, video, and longer text, but adds cost and reduces compatibility across carriers and devices.

RCS (Rich Communication Services) is a newer standard that supports read receipts, typing indicators, high-resolution media, and group chats more like a messaging app, but requires both sender and recipient to have compatible devices and carriers. For broadcast group texting where universal reach matters, SMS remains the most reliable choice because it works on any phone, anywhere.

How SMS gateways work

An SMS gateway is a service that connects a software platform to mobile carrier networks. When you send a message through a group texting platform, the platform passes the message to its gateway, which converts it into the format carriers accept and routes it to the appropriate carrier for each recipient.

The gateway handles the technical complexity of connecting to dozens of carriers across countries, managing delivery acknowledgments, and returning delivery status back to the platform. This is why you can send a text from a web dashboard and it arrives on someone's phone: the gateway bridges the software world and the carrier network.

Short codes versus long codes versus toll-free numbers

A short code is a 5 or 6-digit number like 54321, used by businesses for high-volume messaging. Short codes are leased from the Cellular Telecommunications Industry Association (CTIA), take several weeks to provision, cost several hundred to a thousand dollars per month, and support very high message throughput. They are the standard for large-scale marketing and alert campaigns.

A long code is a standard 10-digit phone number. Long codes are inexpensive and available immediately but have lower throughput limits imposed by carriers. A toll-free number (beginning with 800, 888, 877, etc.) bridges the gap: it supports higher volume than a local long code, is familiar to recipients, and can be provisioned more quickly than a short code. Toll-free numbers also support two-way messaging, making them popular for business texting.

Delivery and carrier filtering

A message being sent does not guarantee it will be received. Carriers apply filtering at several points to reduce spam and protect subscribers. Messages from unknown senders, messages with spam-like content, and messages sent at unusual volumes or patterns are all more likely to be filtered.

Delivery receipts confirm that the message reached the carrier network; actual handset delivery depends on the recipient's phone being on and in coverage. If a phone is turned off or out of range, carriers typically hold the message for up to 72 hours and deliver it when the phone reconnects.

What affects whether your text arrives

Sender reputation is the biggest factor. Carriers track the behavior of sending numbers: high opt-out rates, spam complaints, and unusual sending patterns all damage reputation and reduce delivery rates. Sending from a registered, well-maintained number with a clean, consented list delivers far better than sending from an unregistered number to a purchased list.

Message content also matters. Certain phrases and patterns common in spam trigger carrier filters. Sending realistic volumes from your number type, maintaining a clean list, and writing messages that your subscribers actually want to receive all contribute to reliable delivery.