SMS Regulations

International SMS messaging is subject to country-specific regulations that affect how your messages are sent, what content is allowed, and what registration is required. This page provides a comprehensive reference for Sender ID rules, URL restrictions, content filtering, and detailed compliance requirements for key markets.

Important: Non-compliance with local SMS regulations can result in message blocking, account suspension, or legal penalties. Always check the rules for every country you send SMS to before launching campaigns.

Alphanumeric Sender ID

An alphanumeric Sender ID displays your brand name (e.g., MYBANK) instead of a phone number in the recipient's inbox. EnableX supports alphanumeric Sender IDs, but local regulations vary significantly by country:

Category	What Happens	Action Required
Supported	Alphanumeric Sender ID is delivered as-is	None — just set the Sender ID
Requires Registration	Sender ID must be pre-registered with local operators	Contact EnableX Support with originator, sample text, company website, and use case
Not Supported	Sender ID is overwritten to a local short code or number	Use a local number instead of alphanumeric Sender ID
Requires Local Number	Only local phone numbers are accepted as sender	Purchase a local Long Code or Short Code through EnableX

How to Register a Sender ID

If registration is required for your target country, contact EnableX Support with:

1. The Sender ID (originator) you want to use
2. A sample message text
3. Your company website URL
4. A brief description of your use case

URL Restrictions

In certain countries, URLs in SMS message bodies are blocked by operators unless pre-registered. If you include URLs in your messages, you must register them with EnableX Support before sending.

Note: Shortened URLs (such as bit.ly, tinyurl.com) cannot be registered. You must provide the full URL for whitelisting. Contact EnableX Support with the URL, originator, sample text, and use case description.

Global Sender ID and URL Regulations

The following table summarizes Sender ID support and URL restrictions for countries with specific local regulations. If a country is not listed here, there are no known restrictions on alphanumeric Sender IDs.

Country	Sender ID	URLs	Notes
Argentina	Not supported — overwritten	—
Belgium	Not supported — overwritten (unless local number used)	—
Brazil	Not supported — overwritten	—
Canada	Requires local number	Blocked	URLs in body are blocked. See Canada details
China	Requires registration	Blocked	All content must be whitelisted. See China details
Denmark	Supported	Requires registration
Finland	Supported	Requires registration
France	Supported (marketing: overwritten to short code)	—	See France details
Hungary	Not supported — overwritten	—
India	Requires DLT registration (local traffic)	—	See India details
Japan	Supported	Blocked	See Japan details
Malaysia	Not supported — overwritten	—	See Malaysia details
Nigeria	Requires registration (Airtel, MTN)	—	See Nigeria details
Norway	Supported	Requires registration
Philippines	Requires registration (Smart, Sun)	Requires registration
Romania	Requires registration (DigiMobil, Orange)	Requires registration
Singapore	Supported	—	See Singapore details
South Africa	Not supported — overwritten	—	See South Africa details
Sweden	Supported	Requires registration
Turkey	Requires registration	—	See Turkey details
UAE	Requires registration	—	See UAE details
United States	Requires 10DLC (local number)	Requires registration	See US details

Country-Specific Regulations

The sections below provide detailed compliance requirements for key markets. These are countries where EnableX customers most frequently send SMS and where regulations have the greatest impact on deliverability.

India — DLT Registration

India has one of the most comprehensive SMS regulatory frameworks in the world. All Application-to-Person (A2P) SMS in India must go through the DLT (Distributed Ledger Technology) platform mandated by TRAI (Telecom Regulatory Authority of India).

What DLT Requires

DLT registration is a three-phase process:

Phase 1 — Entity Registration: Register your business as a "Principal Entity" on any operator's DLT portal. You receive a unique Principal Entity ID (PEID) that identifies your organization across all operators.

Phase 2 — Header (Sender ID) Registration: Register your Sender IDs (called "Headers" in DLT terminology) against your PEID. Each Sender ID must be unique and approved.

Phase 3 — Template Registration: Register every message template you intend to send. Each template receives a unique Template ID that must be included in your API calls.

Important: You must share your PEID with EnableX after completing entity registration, along with your approved Sender IDs and Template IDs. Without these, messages to Indian numbers will not be delivered.

Message Categories in India

Category	Description	Time Restrictions
Transactional	OTPs, payment alerts, critical notifications from banks/institutions	Can be sent 24/7
Service Implicit	Order updates, booking confirmations to existing customers (no marketing)	Can be sent 24/7
Service Explicit	Offers and updates to opted-in existing customers	Blocked 9 PM – 9 AM
Promotional	Marketing, advertisements, offers to broader audiences	Blocked 9 PM – 9 AM

Do Not Disturb (DND): Promotional SMS to users registered on the DND list are blocked. Messages sent to DND-registered users during restricted hours (9 PM – 9 AM) are queued and delivered at 9 AM the next day.

International Traffic: Alphanumeric Sender IDs cannot be whitelisted for international traffic to India. Your Sender ID will be overwritten to a short code.

DLT Portal Links

Registration can be done on any operator's DLT portal:

Jio DLT Portal, Airtel DLT Portal, Vodafone-Idea DLT Portal, BSNL DLT Portal, MTNL DLT Portal. Contact EnableX Support for the latest portal URLs and step-by-step registration guidance.

United States — 10DLC

Since March 2021, the United States requires 10DLC (10-Digit Long Code) registration for all Application-to-Person (A2P) SMS. 10DLC is a local 10-digit phone number with registered brand and campaign information that supports throughput up to 30 messages per second.

What 10DLC Requires

10DLC registration is a two-step process:

Step 1 — Brand Registration: Register your business entity with the Campaign Registry. You need your legal company name, EIN/Tax ID, website URL, company address, business vertical, and contact details.

Step 2 — Campaign Registration: Register each messaging use case as a "campaign brief." You must specify the use case type, provide sample messages, and declare opt-in/opt-out mechanisms.

Standard Use Cases

Use Case	Description
2FA	Authentication, verification, one-time passcodes
Account Notifications	Account-related updates for existing customers
Customer Care	Customer interaction and support
Delivery Notifications	Product or service delivery status
Marketing	Promotional content (requires opt-in)
Low Volume Mixed	Multiple use cases at very low volume (test/demo accounts, small businesses)

Important: Unregistered traffic via 10DLC is subject to carrier blocking. Registration is mandatory for A2P messaging in the US. Each 10DLC number must be associated with one brand — shared numbers across brands are prohibited.

Carrier-Specific Fees

US carriers apply additional per-message surcharges on top of EnableX base rates. These fees vary by carrier and are higher for unregistered traffic. Key carriers (T-Mobile, AT&T, Verizon) each have their own registration requirements and fee structures. Contact EnableX Support for current fee schedules.

Getting Started with 10DLC

1. Purchase a dedicated US 10DLC number through EnableX.
2. Gather brand registration information (legal name, EIN, website, address).
3. Prepare your campaign brief (use case, sample messages, opt-in/opt-out details).
4. Submit the registration through EnableX (contact Support or use the portal).
5. Once approved, your use case is assigned a Campaign ID linked to your 10DLC.
6. Start sending registered campaigns using the correct 10DLC as the originator.

Canada

Canada has strict restrictions on SMS sending:

Local Number Required: You must use a local Canadian number as the originator. Alphanumeric Sender IDs are not supported.

URLs Blocked: Messages containing URLs in the body are blocked by the network.

No Bulk SMS: Operators filter and block messages deemed "bulk" in nature. Messages with similar content from the same originator are flagged. To improve delivery, split into smaller groups (<100 messages) with intervals of at least 5 minutes between batches.

Daily Limits: EnableX allows 500 SMS (160 characters each) per number per day, throttled at 1 SMS per second.

Content Filtering: Messages promoting gambling, betting, adult content, and website links are blocked.

Account Whitelisting: Required before you can send to Canadian numbers.

China

Content Whitelisting: Every message content must be whitelisted by local operators before sending. Contact EnableX Support to arrange content whitelisting.

No URLs: All networks block messages containing URLs.

No Binary/Flash SMS: Binary and flash messages are not supported.

Character Limits: Chinese characters require Unicode encoding — max 65 characters per single message, 62 per concatenated segment. Arabic characters are not supported.

Duplicate Protection: You cannot send two messages with the same content to the same number in one day. Maximum 100 different messages per number per day.

Content Filtering: Networks aggressively filter adult content, gambling, financial services, healthcare, education, migration, alcohol, and politically sensitive content.

France

Promotional Restrictions: Marketing/promotional SMS is prohibited between 9:00 PM and 8:00 AM, on bank holidays, and on Sundays. If you send transactional messages (OTPs, notifications) and need to bypass these restrictions, contact EnableX Support to arrange a transactional connection.

Marketing Sender ID: Virtual mobile numbers can only be used for P2P messaging. Marketing content must use a company name as originator (which is overwritten to a short code by operators). This ensures best deliverability for marketing traffic.

Daily Limit: Each number has a daily limit of approximately 500 SMS.

Japan

No URLs: Messages containing URLs are classified as illegal and are either discarded or have the URL removed.

Delivery Reports: Delivery reports from Japanese numbers may not always be reliable.

Character Limits: DoCoMo and Softbank: max 160 characters per SMS. KDDI: max 100 characters per SMS.

Malaysia

Sender ID Overwritten: Alphanumeric Sender IDs are not supported and will be overwritten.

Account Whitelisting: Required before sending.

Message Prefix: All A2P traffic must begin with RM0.00 (indicating free-to-recipient). This consumes the first 7 characters. If you do not include this prefix, operators add it automatically — which may truncate or alter your message.

Character Limit: 153 characters per message (after the mandatory prefix). For concatenated messages, also start with RM0.00.

No Virtual Numbers for A2P: Virtual numbers cannot be used for transactional (OTP) or marketing content — this results in blocking.

Unsupported Characters: Many special characters (€, £, ¥, Greek letters, etc.) are not supported by Malaysian networks.

Singapore

Content Filtering: Content related to gambling, betting, and adult themes is strictly prohibited. Messages with such content are blocked by network operators.

SSIR Registration: For certain use cases, Sender ID registration through the Singapore SMS Sender ID Registry (SSIR) may be required.

Nigeria

DND Registry: Nigeria has a Do-Not-Disturb registry. Users can opt out fully (all third-party messages blocked) or partially (filtered by category). Register your Sender ID with EnableX to bypass DND for critical transactional messages.

Bulk Limits: Bulk SMS of over 2,000 messages may be blocked by some operators (notably Etisalat and MTN).

Operator-Specific Rules: Etisalat filters numeric Sender IDs and bulk SMS >2,000. Glo Mobile filters messages with numbers from other operators. MTN filters the term "MTN" in Sender ID or body.

UAE — United Arab Emirates

Sender ID Registration: Required for all SMS.

Opt-Out for Promotional: All promotional SMS must include opt-out instructions: "To stop receiving, text 'b senderID' to 7726". Messages without this content may be blocked by operators.

South Africa

Sender ID Overwritten: Alphanumeric Sender IDs are not supported.

Two-Way Messaging Restriction: To receive incoming SMS on a virtual number, you must first send an outbound SMS to the recipient from that number. This is a one-for-one system — you cannot receive messages from numbers you have not sent to.

Turkey

Sender ID Registration: Required.

Content Filtering: Gambling-related traffic is strictly prohibited and will be blocked by network operators.

Norway

URL Registration: URLs in SMS must be registered before sending.

Auto Opt-Out: Opt-outs on Norwegian virtual numbers are managed automatically. When users reply with STOP or STOPP, they are automatically unsubscribed and receive a confirmation message.

New Zealand

Best-Effort Delivery: Due to strict operator regulations, SMS delivery to New Zealand is best-effort. Messages may or may not deliver, which is not under EnableX's control.

Dedicated Short Codes: For reliable delivery, procure a dedicated New Zealand short code. Contact EnableX Support for pricing and lead time.

Romania

Sender ID Registration: Required for DigiMobil and Orange operators.

URL Registration: Required.

Two-Way Restriction: Romanian virtual mobile numbers do not have two-way reach to DigiMobile (RCS & RDS) operator numbers.

Compliance Best Practices

Always obtain consent. Before sending any SMS, ensure you have explicit opt-in from the recipient. This is a legal requirement in most countries and a deliverability best practice everywhere.

Provide opt-out mechanisms. Include clear instructions for recipients to unsubscribe (e.g., "Reply STOP to opt out"). Honor opt-out requests immediately.

Register before sending. For countries that require Sender ID, URL, or campaign registration (India, US, Canada, China, etc.), complete all registration steps before sending any messages. Unregistered traffic is increasingly blocked globally.

Respect time restrictions. Several countries restrict promotional SMS during nighttime hours (India: 9 PM–9 AM, France: 9 PM–8 AM plus holidays/Sundays). Sending outside allowed windows results in queuing or blocking.

Avoid filtered content. Gambling, adult content, and certain financial/healthcare topics are filtered in many countries. Verify that your message content is compliant with local regulations before sending.

Test before scaling. Send small test batches to verify deliverability in each target country before launching large campaigns.