SMS (Short Message Service) is a powerful tool for communicating with customers quickly and efficiently. SMS messages can be sent via Spotler SendPro in the same way as email messages. This means all information regarding our API, or for example how Flows and FlowSteps work, apply equally to SMS. However, it's important to be aware of some limitations that can affect the delivery, formatting, and effectiveness of your messages. The information below will help you understand the basic SMS limitations so you can craft better messages and avoid common pitfalls.
- Character Limit
- Unicode and Special Characters
- Message Formatting
- Alphanumeric Sender ID Restrictions
- Delivery Considerations
- Best Practices
Character Limit
Standard SMS Limit
An SMS message can contain up to 160 characters, including spaces and punctuation. If you exceed this limit, your message will be split into multiple segments.
Multipart Messages
When a message exceeds 160 characters, it is broken into multiple parts. Each part is sent as a separate SMS, and the recipient’s phone reassembles them. However, each part reduces the total characters per segment to 153 due to segment identifiers.
Considerations
If your message is longer, consider shortening it or sending it via another channel like email.
Unicode and Special Characters
Basic ASCII Characters
Standard SMS messages use the GSM 7-bit alphabet, which supports basic characters like letters, numbers, and common punctuation marks.
Special Characters
If your message includes special characters outside of the 128 characters allowed by the GSM 7-bit Basic Character Set (emojis, symbols, or non-Latin scripts like Chinese or Arabic), UCS-2 encoding will be employed for the entire message. Messages encoded in this way are limited to 67 characters per segment.
Impact on Cost
UCS-2 encoded messages can increase the number of segments required, leading to higher costs.
Message Formatting
Plain Text Only
SMS does not support rich text formatting like bold, italics, or underlining. All messages are sent in plain text.
Line Breaks
While you can include line breaks in your message, the formatting might not appear as intended on all devices.
URL Handling
Including URLs in your SMS is common, but long URLs might take up a significant portion of the character limit. Consider using a URL shortener.
No Subject or HTML Support
SMS does not support a subject line or HTML content. All messages must be text-only.
Alphanumeric Sender ID Restrictions
What is an Alphanumeric Sender ID?
An alphanumeric sender ID allows you to send SMS messages from a custom name or number instead of a standard phone number. This can be useful for branding and recognition.
Length Restrictions
Alphanumeric sender IDs can be up to 11 characters long and may include both letters and numbers. They cannot include special characters or spaces.
Country-Specific Restrictions
Not all countries support alphanumeric sender IDs. In some regions, the message may default to a local number, or the message may fail to deliver if the alphanumeric ID is not supported.
Compliance Considerations
Some countries have specific regulations regarding the use of alphanumeric sender IDs, and using them may require registration with local authorities or carriers.
Delivery Considerations
Delivery Time
SMS delivery is generally quick, but factors like network congestion, carrier issues, or the recipient’s phone being turned off can cause delays.
Geographical Restrictions
Some countries or regions have restrictions on SMS content or may filter out certain types of messages.
Technical Allowance and Best Effort Delivery
Technically, we allow all SMS messages, with delivery being on a best-effort basis. Upon request or advice, we can help optimize SMS delivery, for example. However, spam is strictly prohibited in accordance with ACM regulations.
Recipient Address Format
All recipient addresses must be stored in the international E.164 format, which ensures consistency and accuracy in message delivery across different countries.
Opt-Outs and Compliance
Always include an option for recipients to opt out of receiving messages to comply when needed, conforming with regulations such as GDPR, TCPA, or CAN-SPAM.
Excluded Countries
SMS services are not available in the following countries:
- Mauritania
- Gabon
- Guinea-Bissau
- Ethiopia
- Réunion
- Saint Pierre & Miquelon
- French Guiana
- Tuvalu
- French Polynesia
- Jordan
- Bhutan
- Turkmenistan
- Georgia
- Kyrgyzstan
- Uzbekistan
- American Samoa
Best Practices
Keep it Short and Clear
Aim to stay within the 160-character limit to avoid splitting your message.
Avoid Special Characters
Use standard ASCII characters to maximize your character limit unless necessary. Avoid using special characters outside of GSM-7 as they can cause delivery issues and may not display correctly on client devices.
Test Before Sending
Send test messages to ensure they appear as intended and are delivered promptly.
Stay Compliant
Always adhere to regulations regarding customer communication, including providing a clear opt-out option.
Consult Before Sending to New Destinations
While we allow sending to all destinations by default, delivery may be suboptimal in some regions. Certain countries, like Turkey, require pre-registration for successful delivery. Without this, messages may be dropped silently. Always consult us before sending to a new destination country to ensure optimal delivery.
For further assistance, feel free to contact our support team at support+sendpro@spotler.com or +31(0)88 – 103 09 09.