Telnyx

Sending SMS internationally requires compliance with country-specific regulations for sender IDs, opt-in consent, content restrictions, and registration requirements. This guide covers the top 10 international messaging destinations and their specific rules.

Quick links: Country-by-country reference · Sender ID types · Opt-in requirements · Content restrictions · Pre-registration

Regulations change frequently. This guide reflects requirements as of early 2026. Always verify current requirements with Telnyx support before launching messaging in a new country.

Sender ID types by country

Not every sender type works in every country. Here’s what’s supported in the top international destinations:

Country	Alphanumeric ID	Long Code	Short Code	Toll-Free	Pre-Registration
🇺🇸 United States	❌	✅ (10DLC)	✅	✅	10DLC required
🇨🇦 Canada	❌	✅	✅	✅	Short code approval
🇬🇧 United Kingdom	✅	✅	✅	—	Recommended
🇩🇪 Germany	✅	✅	✅	—	No
🇫🇷 France	✅	✅	✅	—	OACP required
🇪🇸 Spain	✅	✅	✅	—	No
🇦🇺 Australia	✅	✅	✅	—	Sender ID registration
🇮🇳 India	✅ (registered)	❌	❌	—	DLT mandatory
🇧🇷 Brazil	✅	✅	✅	—	No
🇲🇽 Mexico	✅	✅	✅	—	No

US/Canada note: Alphanumeric sender IDs are not supported for US and Canadian destinations. Use 10DLC, toll-free, or short codes.

Countries requiring pre-registration

Several countries require sender ID or entity registration before you can send messages. Failing to register results in blocked traffic or filtered messages.

Mandatory registration

🇮🇳 India — DLT Registration (Mandatory)

India requires Distributed Ledger Technology (DLT) registration for all A2P SMS. This is the most complex international registration requirement.What you need:

Entity registration on a DLT platform (JioConnect, Vodafone DLT, Airtel DLT, or BSNL DLT)
Header (sender ID) registration — your alphanumeric sender ID must be approved
Template registration — every message template must be pre-approved
Content category — transactional, promotional, or service

Registration steps:

Register as a business entity on one of the DLT platforms
Submit your sender ID (called “header”) for approval
Create and submit message templates
Provide Telnyx with your DLT Entity ID, registered headers, and template IDs

Message categories:

Category	Allowed Hours	DND Filtering	Example
Transactional	24/7	Exempt	OTP, order confirmations
Service (Implicit)	24/7	Exempt	Account updates to existing customers
Promotional	9 AM – 9 PM IST	Applies	Marketing, offers, discounts

Promotional messages to users on the Do Not Disturb (DND) registry will be blocked. Transactional and service messages are exempt from DND filtering.

Template format:

Dear {#var#}, your order {#var#} has been shipped.
Track at {#var#}. Delivery by {#var#}.

Variables are marked with {#var#} and the template must match exactly at delivery time.

🇫🇷 France — OACP Registration

France requires registration through the Off-net Application-to-Person (OACP) framework for commercial SMS.Requirements:

Sender ID must be registered with French carriers
Opt-out must include “STOP” at no cost to the recipient
Commercial messages restricted to 8 AM – 8 PM local time
No commercial SMS on Sundays or public holidays
CNIL (French data authority) consent rules apply

Registration process:

Submit sender ID registration through Telnyx support
Provide business documentation (SIRET number for French businesses)
Allow 5–10 business days for approval

Unregistered sender IDs may be silently filtered by French carriers.

🇦🇺 Australia — Sender ID Registration

Australia’s ACMA requires sender ID registration for A2P messaging.Requirements:

Alphanumeric sender IDs must be registered with carriers
Messages must include opt-out instructions
Commercial messages must comply with the Spam Act 2003
Sender must have consent (express or inferred)

Registration:

Submit sender ID through Telnyx support
Provide Australian Business Number (ABN) or equivalent
Typical approval: 3–5 business days

🇸🇬 Singapore — SSIR Registration

Singapore’s SMS Sender ID Registry (SSIR) requires all organizations to register sender IDs.Requirements:

Mandatory SSIR registration since January 2023
Unregistered alphanumeric sender IDs display as “Likely-SCAM”
Registration through SGNIC (Singapore Network Information Centre)

Process:

Register on the SSIR portal (sgnic.sg)
Submit sender ID with business documentation
Link registered sender ID to Telnyx account via support

Recommended (not mandatory) registration

Country	Registration	Benefit
🇬🇧 United Kingdom	Sender ID pre-registration	Higher delivery rates, reduced filtering
🇩🇪 Germany	None required	—
🇪🇸 Spain	None required	—
🇧🇷 Brazil	Sender ID registration	Better deliverability
🇲🇽 Mexico	None required	—

Opt-in requirements by region

The EU’s GDPR and ePrivacy Directive set the baseline for all EU/EEA countries:

Explicit consent required

Recipients must actively opt in to receive messages. Pre-checked boxes are not valid consent under GDPR.

Purpose limitation

Consent must specify what types of messages the user will receive. “We may contact you” is too vague.

Right to withdraw

Users must be able to opt out at any time, and the process must be as easy as opting in.

Record keeping

Maintain records of when and how consent was obtained. You must be able to prove consent if challenged.

GDPR-compliant consent example:

☐ I agree to receive appointment reminders and order updates from [Company]
  via SMS to the phone number provided. Message frequency: up to 4 msg/month.
  Reply STOP to unsubscribe. Msg & data rates may apply.

Country variations within the EU:

Germany: Requires “double opt-in” (confirmation SMS after initial signup) as best practice
France: CNIL requires explicit, separate consent for marketing SMS
Spain: AEPD allows “soft opt-in” for existing customers (similar products/services only)
Italy: Garante requires clear separation between service and marketing consent

North America

Requirement	United States	Canada
Governing law	TCPA + CTIA guidelines	CASL
Consent type	Express written (marketing) / Express (transactional)	Express or implied
Opt-out mechanism	STOP keyword mandatory	Unsubscribe mechanism required
Record retention	Recommended 4+ years	Duration of consent
Pre-registration	10DLC / toll-free verification	Short code approval

Asia-Pacific

Country	Key requirement
🇮🇳 India	DLT registration + template approval. DND registry filtering for promotional.
🇦🇺 Australia	Express consent required (Spam Act 2003). Include sender identity + opt-out.
🇸🇬 Singapore	SSIR registration. PDPA consent rules. No SMS between 9 PM – 9 AM without consent.
🇯🇵 Japan	Act on Specified Commercial Transactions. Opt-out link required. Sender identification mandatory.
🇰🇷 South Korea	Pre-approved templates only. 080 opt-out number required for commercial messages.

Latin America

Country	Key requirement
🇧🇷 Brazil	LGPD consent required. No messages between 9 PM – 9 AM. Include opt-out.
🇲🇽 Mexico	LFPDPPP consent. Include sender identity. Opt-out mechanism required.
🇨🇴 Colombia	SIC consent requirements. Habeas Data law. Pre-registration recommended.
🇦🇷 Argentina	PDPA consent. National Do Not Call Registry must be checked.

Content restrictions

Universally restricted content

These content types are restricted or prohibited in most countries:

Content type	Status	Notes
Cannabis / CBD	🚫 Prohibited in most countries	Even where locally legal, carriers often block
Gambling	⚠️ Heavily regulated	Requires specific licensing in most jurisdictions
Adult content	🚫 Prohibited	Blocked by most carriers globally
Phishing / fraud	🚫 Prohibited	Immediate account termination
Financial services	⚠️ Regulated	Must comply with local financial advertising laws
Healthcare / pharma	⚠️ Regulated	Prescription drug messaging restricted in many countries
Political campaigns	⚠️ Varies by country	Some countries ban political SMS entirely

Country-specific restrictions

🇬🇧 United Kingdom

Financial promotions: Must be approved by an FCA-authorized firm
Age-gated content: Must use age verification for alcohol, gambling
Charity messaging: Regulated by the Fundraising Regulator
Marketing hours: No legal restriction, but industry best practice is 8 AM – 9 PM

🇩🇪 Germany

UWG (Competition Law): Strict consent requirements for all commercial messages
Heilmittelwerbegesetz: Restricts pharmaceutical advertising
Glücksspielstaatsvertrag: Strict gambling advertising rules
Double opt-in: Expected best practice for marketing consent

🇫🇷 France

Loi Hamon: Right to opt out of all commercial solicitation
Time restrictions: No commercial SMS 8 PM – 8 AM, Sundays, or public holidays
CNIL enforcement: Active enforcement with significant fines
Language: Commercial messages should be in French

🇮🇳 India

Promotional hours: 9 AM – 9 PM IST only (mandatory, not best practice)
DND registry: Promotional messages blocked to DND-registered numbers
Template approval: Every message must match a pre-approved template
Scrubbing: Numbers are checked against DND registry before delivery

🇧🇷 Brazil

LGPD compliance: Explicit consent with specific purpose
Quiet hours: 9 PM – 9 AM (industry standard)
Consumer code: Price/offer messages must include full terms
Language: Messages should be in Portuguese

Country-by-country reference

🇬🇧 United Kingdom

Setting	Value
Sender types	Alphanumeric (recommended), long code, short code
Alphanumeric length	3–11 characters
Regulation	PECR + UK GDPR
Regulator	ICO (Information Commissioner’s Office)
Pre-registration	Recommended (improves deliverability)
Opt-out	STOP keyword or unsubscribe link
Time restrictions	None (best practice: 8 AM – 9 PM)

Send with alphanumeric sender ID:

curl -X POST https://api.telnyx.com/v2/messages \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "YourBrand",
    "to": "+447700900123",
    "text": "Hi! Your delivery is scheduled for tomorrow between 2-4 PM. Reply STOP to opt out.",
    "messaging_profile_id": "YOUR_MESSAGING_PROFILE_ID"
  }'

🇮🇳 India

Setting	Value
Sender types	Alphanumeric only (6 characters, registered header)
Regulation	TRAI + DLT framework
Regulator	TRAI (Telecom Regulatory Authority of India)
Pre-registration	Mandatory — DLT entity, header, and template registration
Opt-out	Handled via DLT/DND registry
Time restrictions	Promotional: 9 AM – 9 PM IST only

India requires both sender ID registration and message template approval before any messages can be sent. Contact Telnyx support to initiate India DLT registration.

🇩🇪 Germany

Setting	Value
Sender types	Alphanumeric, long code
Regulation	GDPR + UWG (Competition Act) + TTDSG
Regulator	BfDI (Federal Data Protection Commissioner)
Pre-registration	Not required
Opt-out	Must be free and easy (STOP keyword or link)
Time restrictions	None legally, best practice 8 AM – 9 PM

🇫🇷 France

Setting	Value
Sender types	Alphanumeric (registered via OACP), long code, short code
Regulation	GDPR + Code des postes et des communications
Regulator	CNIL + ARCEP
Pre-registration	Required — OACP sender ID registration
Opt-out	”STOP” at no cost to recipient (mandatory)
Time restrictions	8 AM – 8 PM, no Sundays/holidays (mandatory for commercial)

🇦🇺 Australia

Setting	Value
Sender types	Alphanumeric (registered), long code, short code
Regulation	Spam Act 2003 + Privacy Act 1988
Regulator	ACMA
Pre-registration	Required (sender ID registration)
Opt-out	Functional unsubscribe within 5 business days
Time restrictions	None legally, best practice 9 AM – 8 PM AEST

🇧🇷 Brazil

Setting	Value
Sender types	Alphanumeric, long code, short code
Regulation	LGPD + Consumer Protection Code
Regulator	ANPD (National Data Protection Authority)
Pre-registration	Recommended
Opt-out	Easy mechanism required
Time restrictions	9 PM – 9 AM quiet hours (industry standard)

🇲🇽 Mexico

Setting	Value
Sender types	Alphanumeric, long code, short code
Regulation	LFPDPPP (Federal Data Protection Law)
Regulator	INAI
Pre-registration	Not required
Opt-out	Mechanism required in privacy notice
Time restrictions	None legally

Best practices for international messaging

Check country requirements before launch

Review this guide and contact Telnyx support for any country not listed. Requirements vary significantly and change frequently.

Use the right sender type

Alphanumeric sender IDs are preferred in most international markets (except US/Canada). They build brand recognition and improve open rates.

Localize your messages

Send messages in the recipient’s language. Many countries require or strongly recommend this for commercial messaging.

Respect time zones and quiet hours

Even where not legally required, sending during business hours dramatically reduces complaints and opt-outs.

Include opt-out in every message

Universal best practice. Use language appropriate to the country (e.g., “STOP” in English-speaking countries, “ARRÊT” in France).

Maintain consent records

Store when and how each recipient consented. GDPR requires you to prove consent if challenged. Keep records for at least 4 years.

Monitor delivery rates by country

Use Message Detail Records to track delivery rates per country. Sudden drops may indicate registration issues or content filtering.

Handling multi-country messaging

For platforms sending to multiple countries, implement country-aware routing:

Python

import telnyx
import os

telnyx.api_key = os.environ["TELNYX_API_KEY"]

# Country-specific configuration
COUNTRY_CONFIG = {
    "US": {
        "from": "+12025551234",  # 10DLC registered number
        "profile": "us-messaging-profile-id",
    },
    "GB": {
        "from": "YourBrand",  # Alphanumeric sender ID
        "profile": "intl-messaging-profile-id",
    },
    "IN": {
        "from": "YRBRAND",  # 6-char registered DLT header
        "profile": "india-messaging-profile-id",
    },
    "DEFAULT": {
        "from": "YourBrand",
        "profile": "intl-messaging-profile-id",
    },
}


def send_international_sms(to: str, text: str, country_code: str):
    """Send an SMS with country-appropriate sender and profile."""
    config = COUNTRY_CONFIG.get(country_code, COUNTRY_CONFIG["DEFAULT"])

    message = telnyx.Message.create(
        from_=config["from"],
        to=to,
        text=text,
        messaging_profile_id=config["profile"],
    )
    return message


# Usage
send_international_sms("+447700900123", "Your order shipped!", "GB")
send_international_sms("+12025559876", "Your order shipped!", "US")
send_international_sms("+919876543210", "Your order shipped!", "IN")

Node

import Telnyx from "telnyx";

const telnyx = new Telnyx(process.env.TELNYX_API_KEY);

const COUNTRY_CONFIG = {
  US: { from: "+12025551234", profile: "us-messaging-profile-id" },
  GB: { from: "YourBrand", profile: "intl-messaging-profile-id" },
  IN: { from: "YRBRAND", profile: "india-messaging-profile-id" },
  DEFAULT: { from: "YourBrand", profile: "intl-messaging-profile-id" },
};

async function sendInternationalSms(to, text, countryCode) {
  const config = COUNTRY_CONFIG[countryCode] || COUNTRY_CONFIG.DEFAULT;

  const { data: message } = await telnyx.messages.create({
    from: config.from,
    to,
    text,
    messaging_profile_id: config.profile,
  });
  return message;
}

// Usage
await sendInternationalSms("+447700900123", "Your order shipped!", "GB");
await sendInternationalSms("+12025559876", "Your order shipped!", "US");

Next steps

Alphanumeric Sender ID

Set up branded sender IDs for international messaging.

Message Encoding

Handle character encoding for international scripts (Arabic, Chinese, etc.).

Error Code Reference

Understand delivery errors including country-specific rejections.

10DLC for US

US-specific registration for A2P messaging.

Sending Messages

Messaging Profiles

Short Code

RCS

Hosted Numbers

Opt Outs

Phone Numbers

Toll Free Verification

10 DLC

International SMS Compliance Guide

Sender ID types by country

Countries requiring pre-registration

Mandatory registration

Recommended (not mandatory) registration

Opt-in requirements by region

North America

Asia-Pacific

Latin America

Content restrictions

Universally restricted content

Country-specific restrictions

Country-by-country reference

🇬🇧 United Kingdom

🇮🇳 India

🇩🇪 Germany

🇫🇷 France

🇦🇺 Australia

🇧🇷 Brazil

🇲🇽 Mexico

Best practices for international messaging

Handling multi-country messaging

Next steps

Alphanumeric Sender ID

Message Encoding

Error Code Reference

10DLC for US

Sending Messages

Messaging Profiles

Short Code

RCS

Hosted Numbers

Opt Outs

Phone Numbers

Toll Free Verification

10 DLC

​Sender ID types by country

​Countries requiring pre-registration

​Mandatory registration

​Recommended (not mandatory) registration

​Opt-in requirements by region

​Europe (GDPR + ePrivacy)

​North America

​Asia-Pacific

​Latin America

​Content restrictions

​Universally restricted content

​Country-specific restrictions

​Country-by-country reference

​🇬🇧 United Kingdom

​🇮🇳 India

​🇩🇪 Germany

​🇫🇷 France

​🇦🇺 Australia

​🇧🇷 Brazil

​🇲🇽 Mexico

​Best practices for international messaging

​Handling multi-country messaging

​Next steps

Alphanumeric Sender ID

Message Encoding

Error Code Reference

10DLC for US

Sender ID types by country

Countries requiring pre-registration

Mandatory registration

Recommended (not mandatory) registration

Opt-in requirements by region

Europe (GDPR + ePrivacy)

North America

Asia-Pacific

Latin America

Content restrictions

Universally restricted content

Country-specific restrictions

Country-by-country reference

🇬🇧 United Kingdom

🇮🇳 India

🇩🇪 Germany

🇫🇷 France

🇦🇺 Australia

🇧🇷 Brazil

🇲🇽 Mexico

Best practices for international messaging

Handling multi-country messaging

Next steps