Sender ID
The sender identity a message appears to come from, alphanumeric, numeric or a short code, and how markets register it.
Definitions only — a term explained here is not a service we sell.
A sender ID is the phone number, short code or alphanumeric string a message appears to come from. Which kinds a market accepts, and whether each needs registration, is a per-market rule.
Registration happens before traffic flows, not after a batch is blocked. It is tied to the exact string and often the content. A brand name that cannot receive STOP messages is a compliance problem.
Three kinds
An alphanumeric sender ID shows a brand name, commonly up to 11 characters, and usually cannot receive replies. A long number is a full MSISDN that can receive replies and is portable. A short code is a national numeric address for high-volume traffic. Each has its own registration path. The market's rules and the need for replies drive the choice.
The three sender types
| The three sender types | Alpha sender | Short code | Long number |
|---|---|---|---|
| Reply path | Usually no | Yes | Yes |
| Registration | Per market | National allocation | Per market |
| Best for | One-way alerts | High-volume two-way | Two-way with a local number |
Text description
An alphanumeric ID carries a brand name and usually cannot receive replies. A long number can, and a short code serves high-volume traffic.
Per-market rules
Some markets allow alphanumeric IDs without registration, some require the sender to be registered and whitelisted, and some overwrite it with a local number. The sender ID in Mexico and Brazil note covers both markets.