Carrier Partners SMS Compliance

When you send SMS through CallHippo’s carrier partners, your messages must follow each destination country’s messaging rules. This guide covers the general best practices and the country-specific requirements that keep your traffic compliant and deliverable.

General best practices

Wherever you send messages, these practices apply:

• Get opt-in consent from every recipient before you send any communication, especially marketing or other non-essential messages.
• Only message during the recipient’s local daytime hours unless the message is urgent.
• Support HELP and STOP keywords (and similar messages) in the recipient’s local language.
• Never contact people who are on do-not-call or do-not-disturb registries.

Carrier partners strongly encourage you to review your proposed use cases with qualified legal counsel to make sure you comply with all applicable laws.

Australia

Sending gambling-related content is strictly prohibited in Australia. All commercial electronic messages sent to an Australian address are governed by the SPAM Act (2003), and it is your responsibility to comply. The key rules are:

• Permission (consent) — messages can only be sent with the permission of the person who owns the account for the address (usually the recipient).
• Identification — messages must include the name and contact details of the person or business that authorized the message.
• Unsubscribe — messages must offer a low-cost or no-cost way for the recipient to opt out.

United States

U.S. telecommunications providers may assess fees for non-compliant A2P traffic, and carrier partners will pass these fees on to you. T-Mobile is the first U.S. provider to announce non-compliance fees for violations of its Code of Conduct:

• 10DLC long code messaging program evasion — a $1,000 pass-through fee if a program is found using techniques such as snowshoeing or unauthorized number replacement/recycling.
• Content violation — after prior warning, a $10,000 pass-through fee may be imposed for each unique instance of content that violates the T-Mobile Code of Conduct. This includes SHAFT (Sex, Hate, Alcohol, Firearms, Tobacco) violations, spam, phishing, and Severity 0 violations as defined in the CTIA Short Code Monitoring Handbook.

United Kingdom

SMS-to-voice functionality is widely used in the UK, so carrier partners will not reject messages sent to landlines. Keep this in mind, as it may not be the behavior your application expects — contact support if you need this changed. Review your use cases with qualified legal counsel to ensure compliance.

India

To comply with local regulation, domestic transactional, domestic promotional, and international SMS messages are sent through mobile operators’ International Long Distance Operator (ILDO) connections. Pre-registered alphanumeric Sender IDs are not supported; messages are delivered with random ILDO-approved short codes in the format 5NNNN–5NNNNNNNN (for example, 54321). Messages bypass India’s Do-Not-Disturb (DND) database and are delivered without time-of-day restrictions.

France

French mobile networks block marketing SMS traffic between 10pm and 8am, on Sundays, and on French public holidays. Messages sent during these restricted times are queued and delivered the following day. Bouygues Telecom does not support Unicode body encoding for A2P SMS, so Unicode characters are replaced with GSM characters to ensure delivery.

Malaysia

Only Person-to-Person (P2P) messages may be sent via Malaysian domestic long codes. For Application-to-Person (A2P) messages, use international long codes. Keep these rules in mind:

• Include your brand name in every message to avoid blocking and filtering by mobile operators.
• The Sender ID of A2P messages to Malaysia is overwritten with a shortcode Sender ID.
• Political, religious, and gambling-related content is strictly prohibited.
• Add the content header RM 0.00 to every message so subscribers know they were not charged. Without it, content may be truncated or fail entirely.
• Concatenated messages are supported by all mobile operators except Digi Malaysia, which delivers them as separate messages.

Philippines

Mobile operators do not allow messages with long international codes — these are overwritten with a generic alphanumeric Sender ID outside the carrier partner’s platform, so sending from a registered alphanumeric Sender ID is strongly recommended. Additional rules:

• Sender IDs containing words such as “TEST”, “MESSAGE”, or “SMS” (or permutations) are not allowed, and Sender IDs that imitate other networks are prohibited.
• Commercial and promotional messages may only go to subscribers who have specifically opted in, and you must provide an opt-out method with regular opt-out instructions.
• Adult content and any mention of alcohol, drugs, gambling, politics, or tobacco is prohibited.
• Shortened URLs are not allowed, and banking-related content with a URL must use allow-listed message templates.

South Africa

Direct marketing messages are regulated under Article 16 of the WASPA Code of Conduct. Unless the consumer has agreed otherwise, marketing messages should not be sent on Sundays and public holidays, on Saturdays before 9am or after 1pm, or on any other day between 8pm and 8am.

Sweden

Swedish mobile operators block and filter SMS content containing web addresses (URLs). If your content includes a URL, contact carrier partner support to have it added to an allow list. Once content registration is complete, send messages with an international long code Sender ID or an alphanumeric Sender ID — using a domestic long code Sender ID may cause URL-containing messages to be filtered.

Turkey

Turkish carriers filter traffic with numeric and unregistered alphanumeric Sender IDs, so pre-register your alphanumeric Sender ID to ensure delivery. P2P traffic and content related to gambling, politics, and religion are prohibited. Since February 15, 2021, and until further notice, promotional traffic to Turkey is prohibited — submitting it may result in your messages and Sender ID being blocked, and possible financial penalties.