Mobile carriers and messaging providers use advanced filtering systems to protect recipients from spam and unwanted messages. If your SMS isn’t being delivered, it’s often due to content, compliance, or sending behavior that triggered those filters. This guide outlines best practices to improve deliverability and reduce the risk of your messages being blocked.
1. Identify Your Business Clearly
Every message should include your company name and make it clear why you’re contacting the recipient.
Example:
Hi Sarah, this is Jordan with [Your Company Name]. I’m reaching out regarding your recent inquiry. Reply STOP to opt out.
Clear identification builds trust and reduces filtering risk.
2. Include Opt-Out Instructions
For marketing or outreach messages, include:
Reply STOP to opt out.
Carriers expect clear opt-out language. Omitting it increases filtering risk.
3. Avoid Spam-Like Language
Certain wording patterns are commonly blocked by carriers.
Avoid:
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FREE!!!
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URGENT
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Act Now
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Limited Time
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Guaranteed
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Excessive punctuation or ALL CAPS
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Overuse of emojis
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Financial distress language
Instead, use a professional tone, clear explanations, and conversational language.
4. Avoid Link Shorteners
Do not use services like bit.ly or tinyurl. Use your own branded domain whenever possible. Carriers trust branded domains more than generic short links.
5. Match Your Messaging to Your Approved Use Case
If you’ve registered your messaging campaign, make sure your actual messages match the described purpose. Do not send marketing under a customer care campaign, and do not send promotional blasts if you registered for appointment reminders. Misalignment increases filtering risk.
6. Control Sending Volume
Sudden spikes in volume can trigger filters. Gradually increase volume when using a new number. Avoid blasting large lists all at once. Maintain consistent sending patterns and monitor opt-out and complaint rates.
7. Personalize When Possible
Carriers favor natural, human-like messaging.
Better:
Hi David, thanks for connecting yesterday. Just following up as discussed.
Riskier:
Hi Friend, we have an offer for you.
Personalization and context reduce the appearance of mass spam.
8. Keep Message Frequency Reasonable
Avoid sending multiple messages in a short period, repeated follow-ups without response, or over-messaging inactive contacts. Respecting frequency improves long-term deliverability.
9. Monitor Performance Regularly
Watch for increased opt-outs, delivery drops, and customer complaints. If you see negative trends, adjust content and volume quickly.
Quick Deliverability Checklist
Before sending, confirm:
✔ Your business name is included
✔ Opt-out instructions are present
✔ The message matches your registered campaign
✔ No spam trigger words are used
✔ Links use a branded domain
✔ Volume increases are gradual
Maintaining compliant, professional messaging protects your deliverability and your brand reputation. If you need help reviewing your message templates or campaign setup, contact support and we’ll help you optimize before you send.
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