The sender ID is the name shown instead of a phone number, at the head of the conversation. A message from CALISERO carries different trust than one from +40770123456.
Format rules
An alphanumeric sender ID holds at most 11 characters. Letters, digits and spaces are allowed; diacritics, emoji and special characters are not. It cannot be digits only — that would be read as a number.
Pick something the customer recognises instantly: the brand name, not an internal abbreviation. THESTORE says nothing; BRAND NAME says everything.
An alphanumeric sender cannot receive replies
This is the limitation nearly everyone forgets on their first integration. Messages sent from an alphanumeric sender ID are one-way — the recipient cannot reply.
If your flow needs a reply (confirmation by "YES", unsubscribe by "STOP"), you need a number, not a name. If it does not, alphanumeric is the right choice.
Consistency beats creativity
Use the same sender ID for the same kind of communication, every time. Customers learn the pattern: security codes come from one name, delivery notices from another. When the pattern changes without explanation, the message looks like fraud — and gets treated as such.
Avoid seasonal changes like BRAND BF for Black Friday. You gain no attention and lose the recognition you built.
Separate sensitive traffic
It is worth having a distinct sender ID for security messages — OTP codes, sign-in alerts. You keep it clear of any commercial content, monitor it separately and route it at the highest priority.
What never to do
Do not use another company's name. Do not imitate banks, couriers or public institutions. Do not add words that manufacture urgency. Beyond the legal side, carriers filter these patterns aggressively, and once you land on a filter list, getting off is hard.
Sender reputation is built from consistent, expected, useful messages. There is no shortcut.
