What is a sender ID?

Short answerA sender ID is the name or number a recipient sees as the sender of a text — your brand name instead of a phone number. In most countries it must be registered with the mobile operators before any traffic will pass, and unregistered traffic is increasingly blocked or silently discarded.

What types of sender ID are there?

• Alphanumeric — your brand name, up to 11 characters. Recognisable, but the recipient cannot reply.
• Long number — a standard mobile number. Two-way, and useful where alphanumeric IDs are not permitted.
• Short code — a 4-6 digit number. Expensive, high-throughput, country-specific.
• 10DLC — the registered long-code route for A2P traffic in the United States.

Why does registration take so long?

Because each country runs its own process, and several run it through a central regulator rather than the operators. You submit documentation about your company and about the content you intend to send, and it is reviewed.

Expect a few days in the easiest markets and several weeks in the strictest — India, the UAE and Saudi Arabia among them. This, not the engineering, is what sets the date you can go live, which is why it should be the first thing you start rather than the last.

What happens if you skip it?

In a growing number of markets, nothing visible: the message is accepted by the gateway, billed, and discarded by the operator without a failure notice. That is the single most common explanation for a delivery rate that looks inexplicably low in one country while every other market is fine.