Text, SMS, and RCS
Your SMS campaign could have perfect timing, compelling copy, and laser-focused targeting—but none of that matters if your messages get blocked before they reach your audience.
Poor SMS deliverability costs businesses real revenue every year. Carriers filter suspicious messages, spam flags block legitimate communications, and infrastructure issues prevent delivery. You end up paying for messages that never make it to the people you want to reach.
SMS deliverability measures how many of your messages successfully arrive in recipients’ inboxes. While SMS boasts higher open rates than email, those impressive numbers only count if your messages get delivered first.
This guide covers what drives SMS deliverability, how to measure and monitor it, common problems that hurt performance, and proven strategies to keep your messages reaching your audience.
What is SMS deliverability?
SMS deliverability measures how many of your text messages actually reach recipients’ devices.
Deliverability differs from other SMS metrics like open rates or click-through rates. Messages must reach the device before recipients can read or act on them—making deliverability your foundation metric.
Poor deliverability wastes your budget and skews your campaign data. A drop from 98% to 90% delivery might seem small, but across one million messages, that’s 80,000 people who never received your text—and 80,000 messages you paid for that accomplished nothing.
Industry benchmarks suggest aiming for 95% or higher delivery rates. Anything consistently below that signals problems with your compliance, content, infrastructure, or sender reputation.
How to calculate and track SMS delivery rate
The SMS delivery rate formula is straightforward:
Delivery Rate = (Messages Delivered ÷ Messages Sent) × 100
If your platform shows 48,500 delivered messages out of 50,000 sent, your deliverability rate is 97%.
Most SMS platforms provide delivery receipts with status codes that show what happened to each message:
Delivered: The recipient’s device received the message Failed: The message couldn’t be delivered due to invalid numbers, carrier rejection, or technical issues
Pending/Unknown: The carrier hasn’t confirmed delivery yet
Single delivery reports are useful, but tracking rates across campaigns, carriers, and regions gives you better insights. A drop in one region might signal local filtering rules. A sudden decline across all campaigns could indicate sender reputation problems.
Common SMS deliverability problems
Even well-planned SMS campaigns face obstacles. Messages get flagged as spam, filtered by carriers, or lost due to technical problems. Most deliverability challenges have clear causes and solutions.
Carrier spam filtering
Carriers actively filter messages they suspect are spam. Their algorithms consider message volume, content patterns, and sending behavior.
Common triggers:
- Too many identical messages sent quickly
- Excessive capitalization or certain flagged words
- Repeated suspicious URL patterns
Solution: Spread large sends over time, vary your content slightly, and follow carrier guidelines. Carriers act as gatekeepers—earn their trust with professional, compliant messaging.
Generic short links hurt trust and deliverability
Using generic URL shorteners like bit.ly or tinyurl is one of the costliest SMS mistakes. Carriers know spammers hide malicious links behind these domains, so they frequently block messages containing them.
Even when these messages get through, generic links reduce trust. Recipients hesitate to click unfamiliar URLs, hurting your engagement rates.
Solution: Use branded short links instead. Create custom domains like yourbrand.link/sale that recipients recognize and trust. Branded links improve deliverability by avoiding carrier filters and boost engagement—data shows click-through rates can increase up to 39% compared to generic URLs.
Sender reputation problems
Carriers assign reputation scores to your sender IDs and numbers. Poor reputation from spam flags, inconsistent sending patterns, or questionable practices can get your messages throttled or blocked.
Solution: Build carrier trust by:
- Using consistent sending patterns
- Only messaging explicit opt-in subscribers
- Avoiding sudden volume spikes without advance notice
Think of reputation as a credit score for SMS—better scores mean carriers let more of your messages through.
Content and compliance violations
SMS faces strict regulations. GDPR applies globally, while U.S. laws like TCPA require explicit opt-ins, clear opt-out instructions, and timing restrictions. Content violating these rules or including prohibited categories can be blocked entirely.
Solution: Follow compliance best practices consistently. Use double opt-in when possible, include “Reply STOP to unsubscribe,” and avoid prohibited content. Compliance preserves deliverability and protects you from fines.
Technical infrastructure problems
Poor SMS provider infrastructure can hurt deliverability through:
- Incorrect sender ID setup
- Low-quality gateway routing
- Missing redundancy in delivery paths
Solution: Choose providers with strong carrier relationships and robust infrastructure. Ensure your sender IDs are properly registered and tested across different carrier networks.
Best practices for maximum SMS deliverability
Beyond solving problems, proactive steps can significantly improve your delivery rates and engagement.
Use branded short links consistently
Custom domains like yourbrand.link/sale signal legitimacy to carriers while building recipient trust. This simple change protects against spam filters and can boost click-through rates by up to 39%.
For detailed guidance on creating and managing branded short links, see our complete guide on how to shorten a link with custom domains.
Build quality subscriber lists
Subscriber quality directly affects deliverability. Clean lists with engaged users maintain healthy sender reputation.
Essential practices:
- Double opt-in: Confirm subscriptions with follow-up messages
- Clear unsubscribe options: Make opting out simple and obvious
- Regular list cleaning: Remove inactive or invalid numbers consistently
Write carrier-friendly content
Balance clarity, compliance, and professionalism in your messaging:
- Avoid spam trigger words like “FREE!!!” or “ACT NOW!!!”
- Personalize messages when possible (“Hi Sarah, your order is ready”)
- Keep messages concise but informative—overly long texts may get split or flagged
Maintain solid technical infrastructure
Key components:
- Reliable SMS platforms: Choose providers with proven delivery rates and established carrier relationships
- Domain authentication: Configure DNS records correctly for each branded domain
- Monitoring systems: Set up alerts for sudden delivery drops so you can respond quickly
Monitor your SMS deliverability performance
Track these four key metrics to catch issues before they hurt your campaigns:
Delivery rate: Your primary indicator of deliverability health—track the percentage of messages that reach recipients versus those that fail.
Message failure reasons: Carriers provide specific error codes when messages fail. Monitor these to identify whether problems stem from invalid numbers, carrier blocks, or technical issues.
Opt-out rate: Rising unsubscribe rates signal content or frequency problems. Carriers notice these increases and may implement filtering measures.
Click-through rate: Sudden CTR drops can indicate delivery problems affecting message reach, even though clicks happen after delivery.
Use analytics dashboards that combine deliverability and performance data for complete visibility. Regular monitoring also reveals optimization opportunities through testing different send times, content variations, and link structures.
To maximize your link tracking capabilities across all marketing channels, learn more about UTM links and campaign tracking best practices.
For comprehensive SMS campaign tracking beyond basic deliverability, explore the top 10 SMS marketing analytics you need to track to understand audience behavior and optimize performance.
Protect your SMS investment
SMS deliverability determines whether your campaigns succeed or fail. Strong deliverability requires attention to sender reputation, carrier filtering, compliance, content quality, and infrastructure.
One of the most effective improvements is replacing generic short links with branded alternatives that avoid spam filters while building recipient trust. When you prioritize deliverability fundamentals, you protect your SMS investment and create stronger customer connections.
Ready to implement these SMS strategies? Explore our SMS marketing best practices guide for additional tactics to improve engagement and compliance across all your text campaigns. Or sign up for a demo to learn how Rebrandly can enhance your SMS deliverability.rebrand