An SMS sender ID is the name or number that appears as the sender of a text message, and the rules for it are set country by country: some markets accept any alphanumeric sender ID, many require you to register it first, and some replace it with a local number. Before you send, check three things for each destination: whether alphanumeric names are supported, whether registration is required, and what happens to unregistered traffic.
This guide explains the sender ID types, why pre-registration exists, and then sets out the rules for 40 major markets in one table. The same rules apply whether you send from our web platform or through the SMS API.
What types of SMS sender ID are there?
There are four common sender types. Which ones you can use depends on the destination country and the network, not on your provider.
| Sender type | What the recipient sees | Can recipients reply? | Typical use |
|---|---|---|---|
| Alphanumeric | A brand name of up to 11 characters, for example AcmeBank | No | OTPs, alerts and marketing where supported |
| Numeric long code | A standard mobile or virtual number | Yes, where two-way is supported | Conversations, support, markets without alphanumeric |
| Short code | A 4 to 6 digit number | Usually yes | High-volume campaigns, keyword opt-ins, some OTP routes |
| Toll-free number | A toll-free format number, for example in the US and Canada | Yes | Verified A2P traffic in North America |
Two terms appear often in country rules. Dynamic means you can set any sender ID per message without registering it. Sender ID replacement means the network or route overwrites whatever you send with a local short code or long code, so recipients never see your brand name.
What is sender ID pre-registration and why is it required?
Pre-registration means your sender ID is approved and linked to your company before any traffic is sent. Regulators and operators introduced it to stop scammers from spoofing bank, delivery and government names. The approach differs by country:
- Labelling. In Singapore, unregistered sender IDs have been labelled “Likely-SCAM” since 31 January 2023, according to the IMDA. Ireland’s regulator ComReg has applied a “Likely Scam” label to unregistered IDs since 3 July 2025, with blocking to follow at a later date, as set out on its SMS Sender ID Registry page. In Australia, messages from unregistered branded sender IDs are labelled “Unverified” under the ACMA SMS Sender ID Register, whose rules apply from 1 July 2026.
- Blocking. In Spain, the CNMC states that from 7 June 2026, messages sent with alias not entered in its registry must be blocked.
- Operator registration. In many markets, including the Gulf states, Nigeria and much of Asia, each network keeps its own approved list and filters anything else.
Registration usually asks for the sender ID, the message type (OTP or marketing), sample content including any URLs, and your company name, address and website, as listed in SMS.to’s sender ID requirements. Some countries charge set-up or monthly fees.
What sender ID do you need for the United States and Canada?
Neither country supports alphanumeric sender IDs. In the United States, A2P traffic runs on registered 10DLC numbers, verified toll-free numbers or short codes, and carriers expect senders to follow the CTIA Messaging Principles and Best Practices on consent and opt-out. On SMS.to routes, a sender ID sent to US or Canadian numbers is replaced by a registered toll-free number. For how each option looks to customers and when to choose it, read 10DLC vs short code vs toll-free.
Sender ID rules in 40 major markets
The table below reflects SMS.to’s published route requirements (last updated May 2026) and, where noted, the regulator’s own rules. “Registration required” means your sender ID must be approved before live traffic. Where local and international traffic differ, the note explains which applies.
| Country | Alphanumeric supported? | Registration required? | Notes |
|---|---|---|---|
| United States | No | Yes | 10DLC, toll-free or short code only; sender replaced by a registered toll-free number |
| Canada | No | Yes | Sender replaced by a registered toll-free number |
| United Kingdom | Yes | Yes | No national registry; brands can protect names through the MEF SenderID Protection Registry |
| Ireland | Yes | Yes | ComReg registry; unregistered IDs labelled “Likely Scam” |
| Spain | Yes | Yes | CNMC Alias Registry; unregistered alias blocked from 7 June 2026 |
| France | Yes | Yes | Marketing restricted to permitted hours; opt-out required in marketing text |
| Germany | Yes | No | Alphanumeric accepted without pre-registration |
| Italy | Yes | Yes | Alias entered in the AGCOM alias register by an authorised provider |
| Netherlands | Yes | No | Alphanumeric accepted without pre-registration |
| Poland | Yes | No | URLs must be whitelisted before sending or messages fail |
| Greece | Yes | No | Up to 11 characters; numeric sender IDs not supported |
| Cyprus | Yes | Yes | Whitelisting of the sender ID only |
| Turkey | Yes | Yes | Commercial messages also need recipient permissions recorded in İYS |
| United Arab Emirates | Yes | Yes | Marketing sender names carry the “AD-” code; no marketing 9pm to 7am (TDRA) |
| Saudi Arabia | Yes | Yes | Only pre-registered names; “-AD” suffix on advertising names; no promotional messages 10pm to 9am (CST rules) |
| Qatar | Yes | Yes | Registration on all networks |
| Kuwait | Yes | Yes | Registration on all networks |
| Egypt | Yes | Yes | Registration on all networks |
| Nigeria | Yes | Yes | Sender ID must also appear in the message text; DND filters promotional traffic |
| Kenya | Yes | Yes | Pre-registered sender IDs on all networks |
| South Africa | Yes, with restrictions | Yes | Sender ID should also be included in the message text |
| Ghana | Yes | Yes | Pre-registered sender IDs on all networks |
| India | Domestic only | Yes, for domestic traffic | Domestic headers (max 11 characters) and templates registered under TRAI rules; international traffic shows a static short code |
| Pakistan | Yes | Yes | Pre-registered alphanumeric or short code senders |
| Bangladesh | Yes | Yes | Register before sending |
| Sri Lanka | Yes | Yes | Registration on all networks |
| China | No | Yes | Sender replaced by a static long code; message template and company signature must be registered |
| Indonesia | Yes | On some networks | Registration for Telkomsel, XL Axiata and Smartfren; dynamic on Indosat and Hutchison routes |
| Philippines | Yes | Yes | Pre-registered sender IDs on all networks |
| Vietnam | Yes | Yes | Registration on all networks |
| Thailand | Yes | Yes | Registration on all networks |
| Malaysia | No | No | Static short code; brand name in the text; contact details and URLs not permitted |
| Singapore | Yes | Yes | Register with the SMS Sender ID Registry; unregistered IDs labelled “Likely-SCAM” |
| Australia | Yes | Yes | ACMA Sender ID Register; unregistered branded IDs labelled “Unverified”; content whitelisting |
| New Zealand | No | Yes | Sender and content whitelisting |
| Brazil | No | No | Sender replaced by a static short code |
| Mexico | No | No | Sender replaced by a static short code |
| Colombia | No | Yes | Local and international traffic registered; sender switched to a short code |
| Argentina | No | Local traffic only | Sender replaced by a static short code |
| Japan | Yes | No | No pre-registration on international routes |
Country-specific guides go deeper for high-traffic markets. For Nigeria, including DND and the four networks, see our SMS API for Nigeria guide.
How do you choose a sender ID that gets approved?
- Match your brand. Reviewers approve names that clearly belong to your company or trading name. Generic words such as INFO, SMS or VERIFY are often rejected.
- Stay within 11 characters. Alphanumeric IDs are limited to 11 characters, and some markets reserve part of that space, such as the “AD-” code in the UAE.
- Separate OTP and marketing. Several countries approve sender IDs per message type. Using one ID for both risks blocking your OTPs along with your campaigns.
- Keep samples real. Submit the exact templates and URLs you will send. Content that differs from the registration is a common cause of filtering.
- Use a number when you need replies. Alphanumeric IDs are one-way. For surveys or support threads, rent a virtual number where two-way SMS is available.
- Test before launch. Send to real handsets on each major network and check the delivery reports before you release a campaign.
How SMS.to handles sender IDs across countries
When you tell us your target countries, we check each one against current operator rules, prepare the registrations that are needed and tell you which markets will show your brand name and which will show a local number. You then send to every country through the same SMS.to SMS API or web platform, using the sender_id field, and track results with delivery reports. Where a market has marketing hours or opt-out rules, we flag them before you launch. For marketing consent and opt-outs, see SMS marketing compliance and automated opt-outs.
FAQs
What is an SMS sender ID?
It is the name or number shown as the sender of a text message. It can be an alphanumeric brand name, a long code, a short code or a toll-free number, depending on the country.
Can I use any name as my sender ID?
Only in countries that allow dynamic sender IDs. In registration markets, the name must be approved and linked to your company, and in some markets names that imitate protected brands are blocked.
Why does my message show a number instead of my brand name?
The destination does not support alphanumeric sender IDs, or the route replaces unregistered IDs with a local short code or long code. The US, Canada, Brazil, Mexico and China are examples.
What happens if I send with an unregistered sender ID?
Depending on the country, the message is blocked, delivered with a warning label such as “Likely-SCAM” or “Unverified”, or delivered with a replaced sender.
How many characters can an alphanumeric sender ID have?
Up to 11 characters, using letters and digits. Some countries restrict certain characters or reserve a prefix or suffix for marketing traffic.
Rules change often. This guide reflects the rules as of September 2026; check with your account manager before launching a campaign.
Sending to several of these markets? Talk to sales and we will map the sender ID requirements for your country list and handle the registrations with you.
