Number Masking & Sender ID Registration

What is Number Masking?

Number masking means overriding the sender your recipient sees with a numeric string of your choosing, rather than the number the gateway would normally use. It was once common for bulk SMS, but operators across most markets have withdrawn it because it can be used to impersonate banks, government agencies and delivery companies.

Where it is still technically possible, the operator may substitute its own number anyway depending on the route. That behaviour is set at network level and applies to every SMS provider — it is not an iSMS restriction.

Sender ID Registration — What Most Countries Now Require

The replacement for masking is a registered Sender ID: your brand name, submitted in advance and approved by the operator or the national regulator before any traffic is accepted. This is now the norm rather than the exception. It is why messages from banks and large retailers arrive with a name rather than a number.

What Applies Where

Requirements change frequently and differ per operator even within one country. Tell us which destinations you send to and we will confirm the current position and handle the registration for you.

Things to Know Before You Register

• A registered Sender ID is one-way only — recipients cannot reply to it. If you need replies, use Two-Way SMS on a long or random number instead.
• Delivery reports behave differently by route. See SMS Delivery Reports for what is reported on each.
• Sender IDs are capped at 11 alphanumeric characters, with no spaces or special characters.
• Registration is usually tied to specific message content. Approval for OTP traffic does not automatically cover marketing.

Want Your Brand Name on the Message?

If the goal is recognition rather than masking, two routes work well in Malaysia. A registered Sender ID through a Telco short code puts your name in the sender field. Or WhatsApp Business API shows your verified business name and profile photo on every message, supports clickable links, and reports true handset delivery — none of which standard SMS can do in Malaysia.