What is SMS Delivery, and How Can You Reach the Main Inbox?

illustration of mailbox on a phone to symbolize SMS delivery
Posted in
SMS Marketing
Published on
Nov 18, 2022
Written by
Cassi Ettman
Cassi Ettman is a Product Marketing Manager at Attentive. Her favorite part of the day is enjoying her morning coffee, spending time with close friends, or doing Pilates.
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Get our top tips for maximizing SMS delivery and landing in the primary text message inbox.

There are a lot of aspects that go into running a successful SMS marketing program—making sure you’re compliant with legal rules and regulations, growing a healthy and engaged subscriber list, and using different strategies to personalize your text messages

But there’s another aspect that can have a major impact on your program: SMS delivery, or in other words, making sure your text messages reach your subscribers’ main inbox.

Keep reading to learn what SMS delivery is, what causes delivery issues, and best practices for improving delivery and avoiding the spam trap. 

What is SMS delivery?

SMS delivery, similar to email delivery, is a crucial metric that determines the success of your text message campaigns. It represents the percentage of SMS messages that reach their intended recipients' mobile devices without any issues. Just like email marketers track successful email delivery rates, SMS delivery rate is a vital measure for text message marketers.

Conversely, the bounce rate metric is used to gauge the percentage of messages that failed to be delivered. By focusing on SMS delivery, you can ensure that your messages effectively reach your target audience and maximize the impact of your mobile marketing efforts.

Why is SMS delivery important?

You’ve worked hard to grow your subscriber base, but if your text messages aren’t getting through, you’re not able to make the most out of your acquisition efforts. And, if subscribers don’t get your text messages, there’s no way they can convert from SMS, which in turn impacts your program’s ROI. 

Take it from goat milk skincare company Beekman 1802. When they first launched their SMS channel with a different vendor, they were using a 10-digit long code, which was impacting the deliverability of their text messages as 10-digit long codes usually have lower message throughput than short codes (more on that below). 

Beekman 1802 needed an SMS partner with a more powerful platform—and one that could migrate their phone number over to a 5-digit short code, the best type of phone number for their business that would allow them to send more messages faster.

After shopping around for a new SMS partner, Beekman 1802 felt confident about Attentive. “As we were looking at different platforms, Attentive checked all of our boxes—with better deliverability, segmentation, integrations, two-tap sign-up, and more,” said Adam Bshero, VP of Digital Marketing at Beekman 1802. “We also knew we’d be able to have our own short code, which was important.”

Common issues, and tips for maximizing SMS delivery

The first step to maximizing your SMS marketing ROI is understanding how to make sure your text messages make it to your subscribers. And while this list isn’t exhaustive, it should provide you with a good understanding of what can cause issues and the steps you can take to improve SMS delivery.

Sign-up errors

One of the most common causes of SMS delivery failure is a phone number error at sign-up. Sometimes subscribers may accidentally input the wrong phone number, but with the right list growth tools, you can prevent that as much as possible. 


With Attentive’s patented two-tap sign-up technology, subscribers simply tap the button on your sign-up unit, which loads a pre-populated text message on their device. Then, they hit “send” to opt in and start receiving messages from your brand. This strategy means subscribers don’t need to enter their phone number in the first place, therefore preventing errors. 

For desktop sign-up units in which consumers have to manually enter their phone number, make sure you’ve enabled double opt-in. After a potential subscriber has provided their phone number through your sign-up unit, they’ll automatically be prompted to send a message (reply “Y”) from that phone number to confirm they want to be subscribed. Not only can this help ensure the phone number is correct and can receive text messages, but it also helps with compliance, since the subscriber is confirming their opt-in.   

iOS and Android filters

If your subscriber hasn’t saved your brand as a contact in their phone, and your number is considered an unknown sender, there’s a chance your message could be filtered out of their primary text message inbox. 


Send subscribers your virtual contact card (which should contain your brand’s name, logo, and more), and encourage them to add you to their contacts. Another benefit this offers is brand recognition. Instead of seeing your short code or toll-free number, subscribers will see the name of your brand and your logo every time you send them a text. This can lead to lower SMS opt-out rates, too.

Using the wrong type of phone number for your business

There are a few types of phone numbers available to brands when using text message marketing, including dedicated 5- or 6-digit short codes, toll-free numbers, and A2P 10-digit long codes (10DLC). 

Similar to what Beekman 1802 saw, using the wrong type of phone number can have a major impact on your SMS delivery. For smaller businesses or lists, we recommend a toll-free number. For larger businesses, lists, or brands who plan to send mostly MMS, we recommend using a 5- or 6-digit short code. The key benefit with short codes is higher message throughput, meaning you can send more messages faster than a toll-free number or 10DLC.


Choose an SMS marketing partner who has expertise in SMS delivery and can help you determine the right type of phone number for your business.

Carrier spam filters

Carriers (e.g., Verizon, AT&T, T-Mobile, etc) have spam filtering in place to prevent subscribers from receiving unwanted, fraudulent, or spammy messages. When they detect a text message as spam, they’ll stop the message from being delivered to the subscriber. 

Some of the reasons messages get filtered as spam include:

  • Using third-party link shorteners, such as bit.ly, ow.ly, etc, because these are commonly used in spam texts
  • Making exaggerated claims or promises, or including questionable content
  • Not being compliant with carrier policies, or state/local/national regulations


Always comply with SMS rules and regulations, including the Telephone Consumer Protection Act (TCPA), the Cellular Telecommunications Industry Association (CTIA), and the Americans With Disabilities Act for Accessible Design (ADA). You can learn more in our Marketer’s Guide to SMS Compliance.

Avoid using third-party link shorteners in your text messages. Instead, use a branded shortened link (or if you’re an Attentive customer, you can use our built-in URL shortener).  

Personalize your text messages, and be strategic about how often you’re texting your subscribers, how early or how late you’re sending messages, and more. Attentive’s platform has multiple built-in features that can help you keep your text messages out of the spam folder. These include:

  • Smart Sending: limits how many marketing messages can be sent to the same subscriber over a period of time 
  • Quiet hours: restricts when marketing messages can be sent to subscribers (certain messages, such as legal, transactional, and welcome messages, will still be sent during quiet hours)
  • Time zone-based message sending: scans the geographic info for your audience and automatically adjusts the send time based on each subscriber’s local time zone
  • Opt-out reporting per message: helps you monitor each message you send, so you can quickly see opt-out trends that may indicate a text isn’t relevant to the recipient  

How Attentive prioritizes SMS delivery

All of the messages sent and received on our platform flow through the Attentive Delivery Network (ADN). This infrastructure sends and receives billions of messages every month and makes sure your messages get delivered.

  • 10B+ messages sent per year
  • 1.2M messages per minute
  • 71% higher deliverability satisfaction (compared to other SMS platforms; based on a June 2022 survey of Attentive customers)

We also have a dedicated Messaging Operations team that uses advanced monitoring tools to track the deliverability of all messages sent by our customers. These sophisticated systems are proven to provide successful delivery—even during high traffic periods such as Black Friday, Cyber Monday—and enable our team to flag, action, and resolve any deliverability issues promptly if they arise. 

We’re also active with over 80 carriers across the globe, reaching a dozen countries and growing. “The deliverability with Attentive is noticeably stronger [than our previous provider], especially with the relationships they have with carriers,” says Tiffany Chen, Director of Retention Marketing at Oak Essentials.

Working with the right SMS partner is a critical first step in making sure your messages are compliant, getting delivered, and driving revenue. Learn more about why thousands of brands choose Attentive as their #1 SMS marketing solution, and see what we can do for you. Try us for free.

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