SMS - Best Practices for Using Toll-Free Numbers in the US and Canada

This guide explains which SMS and MMS use cases are approved for Toll-Free phone numbers, and our recommendations for high SMS deliverability.

SMS Delivery and Deliverability

SMS Delivery is a measure of the percentage of outgoing SMS and MMS messages which are successfully received at recipients’ mobile devices. It is noted as a Delivered rate in the SMS Message Delivery report. Your open rate can only be high if your messages are delivered.   

SMS Deliverability strictly measures how many messages are delivered versus the number sent in a defined time frame. There is no standard time frame for measuring SMS deliverability, but most often rates are quoted annually, quarterly, or daily. The formula becomes:

The nature of SMS means some percentage of messages will never be delivered. There are just too many variables that can cause message failures.

Common Causes of Text Message Delivery Failure

• Invalid Mobile Numbers or Information

• End/Recipient Device Level Errors and Exceptions

• Telecommunications Networks and Carriers Filtering (Blocking)

The device endpoint is an especially common reason for deliverability issues. Sometimes roaming devices or quickly moving devices do not acknowledge SMS or MMS reception, leading to messages being received more than once, or never received at all. Additionally, sometimes end devices or numbers just can't receive SMS messages. Invalid numbers are another common reason for message delivery problems. Messages sent to changed (or fake) phone numbers won't reach their intended destination, decreasing your message delivery rate. Note that sometimes deliverability issues are intentional - for example, messages judged 'spam' may be blocked by wireless carriers. SMS senders will need to focus on getting messages delivered instead of getting delivered at a certain time due to carrier throughput limits and heavy carrier filtering.

SMS Sending Number Reputation

When you start sending SMS marketing or transaction text messages, the wireless carriers will monitor your traffic, content from your new SMS sending number and behavior of your recipients. This creates a sending number reputation. To notify your recipients of your new SMS number and establish a positive reputation with carriers, we recommend warming up your verified toll-free numbers to optimize deliverability.  

Some key factors used to evaluate SMS sending number reputation by carriers
Opt-out rate – what is the sending number’s opt-out rate?
Sending volume – what is the average volume?
Non-delivery – how many numbers are invalid?
URLs – what type of content is hosted at the URL? Is it using public URL shorteners?
Content filtering – has the content been filtered for violating federal, state or local regulations?

SMS Sending Number Warm-up Best Practices

Content: Avoid using links and sales/promotional langue in the message.
Volume: Start slowly, with less than 200 unique recipients per day for 30 days.
Schedule: Stagger the send times by outputting the lists in multiple groups via Audience Builder and schedule the messages at intervals via Odyssey.
Analytics: Review the Message Delivery report and slow down further if you see spike in opt-outs and bounces.
Cross Marketing: Promote your SMS marketing through other digital marketing channels.

You can find more information at Improving or maintaining SMS Deliverability section below.

SMS: Approved Use Cases

Some categories of messaging, such as high-risk financial services and third-party debt collection, are specifically forbidden on Toll-Free SMS and MMS. For more details, see Forbidden message categories for SMS and MMS in the US and Canada.

Toll-Free messaging is a great choice for transactional use cases, including the following:

• One-time password (OTP) or verification codes

• Account-related alerts or notifications

• Customer care messaging that includes some automated messaging (including satisfaction surveys)

Toll-Free messaging can also be used for promotional or marketing-type traffic, however it is extremely important to ensure that all recipients have opted-in and that you maintain a low opt-out ("STOP" reply) rate to avoid filtering.

SMS Deliverability Best Practices (Improving or maintaining SMS Deliverability)

Before you start using SMS, you must comply with all rules and regulations.
Omeda’s SMS feature is supported by Twilio. The following compliance requirements are in alignment with Twilio’s Messaging Policy.

Additionally, Toll-Free messaging users should adhere to the best practice standards.

• Obtain clear opt-in:
  To send an SMS message to a recipient at Omeda, that recipient must consent to receiving messages of that type to a specific phone number.

  • Clearly explain what consumers are signing up for when they provide their phone numbers.

  • Use double opt-in mechanisms where recipients confirm their consent by replying to an initial message.

  • While consent does not expire at the federal level, it’s generally best practice to ensure opt-ins are within the last 12-18 months.

• Sender Identification:

  • Clearly identify yourself (the party that obtained the opt-in from the recipient) as the sender, except in follow-up messages of an ongoing conversation.

• Personalize Content:

  • Send personalized and relevant messages to your recipients. Create content variability. Each message sent to each recipient should be unique and valued.

  • Include clear opt-out instructions, In the US and Canada this is typically STOP, e.g. "Reply STOP to unsubscribe.” Using alternative phrases like "text 2 to opt out" is not compliant and will result in filtering.

  • Use precise language, and proper capitalization and punctuation.

  • Do not send links that have been shortened using shared public URL shorteners, such as TinyUrl or free Bitly links.

  • Use branded domains you own and control when sending links in your messages.

  • Avoid using emojis, or unnecessary special characters/capitalization.

  • Ensure every message offers value, such as exclusive discounts, important updates, or useful information, to justify the intrusion into the recipient’s personal space.

  • Keep your SMS text at no more than 150-160 maximum characters -- 70 characters if there are any special characters or emojis.

  • When sending text and pictures in the same message (MMS messaging), a message can contain up to 10 images and 1600 characters, as long as the entire message is under 5 MB in size. 1600 characters will take up 4.8 KB, which accounts for roughly 1% of the message size limit. Note 300KB JPG or GIF file format is often mentioned as the largest image size more carriers will reliably handle.

• Segmentation and Targeting:

  • Use segmentation to send targeted messages based on consumer behavior, preferences, and past interactions with your brand.

• Evaluate non-deliverables and unsubscribes:

  • Review message delivery reports for bounces/blocks or a spike in opt-outs or complaints. This is an indicator that there is something that needs to be corrected in your consent or opt-out mechanisms. Carriers will start filtering heavily, or completely block traffic as phone numbers receive complaints/high opt-out rates.

• Respect Frequency:

  • Send around 2-4 messages per month.

• Audit and Update Practices Regularly:

  • Continuously review your marketing practices and legal requirements to stay compliant with any new laws or changes in regulations. Do not send content that is illegal in your sending area or is forbidden by carriers.

How Omeda Helps

Filtering Mitigation Process
Toll-Free message filtering is primarily geared toward preventing unwanted messaging, fraud, or abuse. If you suspect you may be experiencing inappropriate filtering (error 30007) on compliant messages despite adhering to all best practices listed above, please open a ticket and provide 3 or more examples of Message SIDs that have the ‘Carrier Bounce’ status code 30007 within the previous 7 days. You will see the Message SID when you click on Bounced Quantity → Recipients count in Message Delivery report.

Omeda team can try to help reviewing your messaging, determine if an error was made and mitigate the block on your behalf.