• By Charlie Davies
• SMS Marketing

SMS Deliverability Guide: How to Ensure Your Messages Get Delivered

High deliverability is the foundation of successful SMS marketing. Even the most compelling message is worthless if it never reaches your customers. SMS deliverability—the percentage of messages that successfully reach recipients—should be 95% or higher. Anything less indicates serious problems that need immediate attention.

Understanding Carrier Filtering

Mobile carriers use sophisticated filtering systems to block spam and protect consumers. Messages flagged as spam never reach recipients. Common triggers include excessive capitalization, spam keywords, suspicious links, and high-volume sending from new numbers. Understanding carrier rules is essential for maintaining deliverability.

Maintain a Clean Contact List

Invalid or inactive numbers hurt deliverability rates and waste money. Regularly clean your contact list by removing numbers that consistently fail delivery. Implement double opt-in to ensure number validity at signup. Remove contacts who haven't engaged in 6-12 months to maintain a healthy, active list.

Avoid Spam Trigger Words

Certain words and phrases trigger carrier spam filters. Avoid excessive use of words like "free," "winner," "click now," "urgent," or "limited time." While these words aren't banned, overusing them—especially in combination—increases the likelihood of filtering. Write naturally and focus on providing value.

Use Registered and Verified Numbers

Send messages from properly registered phone numbers or short codes. Unregistered numbers face higher scrutiny from carriers. For high-volume sending, consider registering a 10DLC (10-digit long code) number or using a dedicated short code for improved deliverability and brand recognition.

Respect Sending Volume Limits

Sudden spikes in sending volume trigger carrier alarms. If you typically send 1,000 messages per day, don't suddenly send 50,000. Gradually increase volume to establish sending patterns. Use throttling to distribute messages over time rather than sending all at once.

Monitor Engagement Metrics

Carriers track recipient engagement—clicks, responses, and opt-outs. Low engagement signals potential spam. High opt-out rates damage sender reputation. Send relevant, targeted messages that recipients want to receive. Segment your audience and personalize content to maintain strong engagement metrics.

Include Clear Sender Identification

Always identify your business clearly in messages. Carriers and recipients should immediately know who sent the message. Start messages with your business name or include it in your sender ID. Transparency builds trust and reduces spam complaints.

Best Practices for High Deliverability

• • Maintain list hygiene by removing invalid numbers
• • Use registered phone numbers or short codes
• • Avoid spam trigger words and excessive caps
• • Gradually increase sending volume
• • Always include opt-out instructions
• • Send during appropriate hours (8 AM - 9 PM)
• • Monitor engagement and delivery rates
• • Use reputable SMS platforms with good carrier relationships

Frequently Asked Questions

What's a good SMS delivery rate?
95% or higher is the industry standard. Anything below 90% indicates serious deliverability issues that need immediate investigation and correction.

Why are my messages being filtered as spam?
Common causes include spam trigger words, unregistered numbers, sudden volume spikes, poor engagement rates, or too many opt-outs. Review your content and sending practices.

Can I improve deliverability after it drops?
Yes, but it takes time. Clean your list, improve content quality, reduce sending frequency temporarily, and focus on highly engaged segments. Deliverability typically recovers over 2-4 weeks.

Conclusion

SMS deliverability requires ongoing attention to list quality, content strategy, and carrier requirements. By following best practices, maintaining clean lists, and sending relevant messages, you'll achieve consistently high delivery rates. Remember—deliverability isn't just a technical concern, it's a fundamental requirement for SMS marketing success.

Ready to improve your SMS deliverability? Start implementing these best practices today for better results.