Insights & Resources • PUBLISHED 1/4/2021

SMS delivery: Reporting and improving deliverability

Your SMS delivery rate can make or break the success of your business. Learn how to measure and improve your SMS deliverability.

Product Marketing Manager, Telnyx

By Risa Takenaka

Successful SMS delivery image

SMS delivery (also called SMS deliverability) is vital to any text message marketing campaign. If your messages aren’t delivered, your target audience won’t be able to see your message, let alone engage with it.

That’s why finding an SMS platform that gives insight into deliverability reports is so crucial for businesses and marketers alike. In this post, we’ll take a deeper dive into what SMS delivery is and how to get the most out of your text messages.

What is SMS delivery?

SMS delivery is a measure of how many messages were successfully sent to the intended recipient. SMS delivery is expressed as a percentage of the total number of messages you sent. So your SMS delivery rate is the percentage of all the messages you sent which were successfully delivered.

Understanding SMS delivery is important because SMS delivery affects your SMS marketing performance. However, SMS delivery isn’t directly related to the quality of your SMS messages.

Knowing your delivery rate helps you avoid misdiagnosing why your SMS marketing is underperforming. It also enables you to assess the more technical aspects of your SMS campaigns.

Let’s dive deeper into what that means.

Why SMS deliverability matters

The main reason that deliverability matters is that even if you don’t have to pay for undelivered SMS messages, undelivered SMS messages are a missed opportunity.

Knowing your SMS delivery rate enables you to do better conversion rate optimization.

SMS delivery issues are unrelated to how well the actual message is crafted. If your delivery rate is high, but your SMS marketing isn’t performing well, then the issue lies with your message content, sending time, call to action, or something else related to the fundamentals of marketing.

On the other hand, if your delivery rate is low, and your SMS marketing isn’t performing well, that indicates problems with the quality of your phone lists or with your SMS carrier.

It’s critical to have a reporting platform that delivers accurate SMS delivery data. It’s also vital that your reporting platform identifies why a message wasn’t delivered.

Without accurate delivery reporting, diagnosing issues with your SMS marketing is nearly impossible. Conversely, if you have recent, accurate SMS delivery reporting, calculating your SMS delivery rate is simple.

How to measure SMS delivery

The most straighforward way to calculate your SMS delivery rate is to just divide the number of successfully delivered messages by the total number of sent messages. For the mathematically inclined, the formula is as follows:

[ delivered messages ÷ total sent messages = SMS delivery rate ]

That will tell you what percentage of your messages are being delivered as intended.

It’s worth noting that your SMS delivery data won’t tell you when you’ve sent a message to the wrong person. SMS delivery just tells you whether or not the message was successfully delivered to a device so that a person on the receiving end could read the message. If the wrong person reads the message, they’ll probably opt-out (which we’ll talk about in the section about why messages might not be delivered).

Just knowing what percentage of your messages are successfully reaching the intended destination tells you a lot about the quality of your phone lists and how well your SMS carrier is doing their part. So that simple formula can do a lot for you. And a good reporting platform will provide you with direct insights into SMS deliverability and performance.

If your SMS delivery rates look a bit low, here’s what might be happening.

Reasons SMS messages aren’t delivered

If an SMS message isn’t delivered, the problem is either on your end as the sender, in the middle with your SMS provider, or on the recipient’s end. Here are the most common issues that you'll encounter:

  • The phone number is invalid - An invalid phone number is a phone number that’s unassigned. This is different than having the wrong phone number. If you have the wrong phone number, the message can still be delivered—it just gets delivered to the wrong person. Messages to an invalid number are never recieved.

  • Spam filters stopped your message - This won’t happen often, if you send good messages that follow compliance standards. But, if you send messages without opt-out instructions or send too many messages from the same phone number too quickly, spam filters may block your message.

  • The receiving device had an issue - Sometimes roaming devices will fail to report that a message has been received. And sometimes a phone number is connected to a device that simply can’t receive SMS messages. These messages also show as undelivered.

  • Your carrier uses gray routes - Gray routes are message delivery routes that use unauthorized networks to avoid paying third party network operators for transmitting the message.

Most legitimate carriers avoid using gray routes because it's a shady practice. However, some carriers contract out much of their network infrastructure. And, sometimes, the contracted network operators will use gray routes to avoid paying subcontractors.

If your SMS provider sends messages over contracted networks, they may unknowingly be sending your messages over gray routes. Spam filters will block a message sent over gray routes, regardless of why the message ended up on that gray route.

These issues can produce different sorts of delivery problems. But the bottom line is that an SMS message that encounters any of these problems outlined above will end up being undelivered.

The good news is that you can correct most of these issues.

Tips to improve SMS delivery rates

You have control over any delivery issues that occur on your end. Phone numbers and message quality are things that your team can easily correct in order to raise your delivery rates.

Issues with your carrier can also be corrected. And, even though you have no control over what phone a person has, you can take steps up front to avoid sending messages to devices that aren’t capable of receiving them.

Here’s what you can do to improve your delivery rates:

Quality control your phone lists - Even though people have to give you their phone number, people often make mistakes when they enter their phone number in contact forms. People also change their phone numbers.

Regardless of why a phone number might be wrong, you need to validate the phone numbers in your CRM databases to get rid of those invalid numbers that drive delivery rates down.

Include opt-out instructions - Failing to include opt-out instructions is not only a violation of most SMS regulations, it’s also a sure way to trigger spam filters. Make sure your messages tell people how to ask your business to stop contacting them.

Collect phone numbers using a keyword - Using a keyword is one of the best ways to collect phone numbers and get consent to send SMS marketing messages.

Since people must text the keyword to your short code number to subscribe, it’s nearly impossible to get invalid phone numbers using a keyword opt-in. And a keyword opt-in ensures that the phone number is connected to an SMS-capable device.

Switch to a more reliable carrier - If your carrier is causing delivery issues because your messages are traversing gray routes or their networks have data security issues, it’s a sure sign that you should switch to a new SMS provider, like Telnyx.

Telnyx never has issues with gray routes or data security because we own and operate our entire network. Your data never traverses a third party network, so we can guarantee that there are no gray routes involved. And your data is encrypted from end to end. In short, the Telnyx network ensures maximum SMS delivery rates.

Some of these fixes are simpler than others. However, if you’re willing to make a few changes, you can correct almost any SMS delivery problem.

But say you make some changes to improve your SMS delivery. How do you know your efforts are working?

How SMS delivery reporting works

When you send an SMS message, one of two things happens:

  1. The message reaches the device connected to the phone number, and the device reports that it has received the message. This counts as a delivered message.

  2. The message never makes it to the intended destination, and your SMS carrier’s servers attempt to collect information about why the message was not delivered.

Here’s a breakdown of the four results you’ll see on an SMS delivery report:

Delivered - This means the message was successfully delivered, and the receiving device confirmed receipt of the message.

Opted-out - An opt-out means that the message was successfully delivered, and the recipient responded with the opt-out keyword. It’s not a truly undelivered message, but you won’t be able to send messages to that number anymore.

Undelivered (soft bounce) - A soft bounce is a temporary delivery issue. Either the receiving device is off or outside of cell service. A soft bounce isn’t great. But soft bounces usually get delivered eventually.

Undelivered (hard bounce) - Hard bounces are the bad ones. A hard bounce means the message will never be delivered. The phone number might be invalid or connected to a landline. Either way, there’s no reason to continue sending SMS messages to a phone number once you’ve gotten a hard bounce from that number.

When you’re looking over your delivery reports, It’s the hard bounces and opt-outs that should stand out.

If you’re getting a lot of hard bounces and opt-outs, you most likely need to improve your opt-in process to help filter out unusable phone numbers and customers who don’t really want to hear from you.

Lastly, there are a few other metrics to keep an eye on that will help you diagnose delivery issues.

Metrics that matter

Most of these SMS delivery metrics help you evaluate how well your SMS carrier is doing their part. But they also help you assess the reliability of your SMS delivery service and reporting.

Keep an eye on these metrics:

DLR ratio - This is the number of messages that receive a delivery status (whether that’s delivered or undelivered) measured as a ratio against the total number of messages sent. A high DLR ratio is good.

But it’s more important to ensure that your DLR ratio is consistent. Wide variations in your success ratio can indicate issues with your carrier’s delivery reporting. A good SMS API should consistently report whether or not your messages are delivered.

Delivery latency - An SMS delivery status should come with delivery latency information that shows how long it took to deliver the message. Similar to your DLR ratio, the absolute number isn’t as important as the consistency.

Wide variations in delivery latency can indicate potential issues in your carrier’s SMS delivery infrastructure. That doesn’t necessarily mean that your carrier is bad. But more consistent delivery latencies indicate more stable SMS infrastructure and fewer network hops, which means more security.

Use case specific metrics - Obviously it’s important to track the metrics that tell you whether or not your SMS messages are performing as intended.

If you’re using SMS for two-factor authentication (2FA), it’s important to track successful logins and alternate authentication uses. If users must frequently opt to receive an email for their 2FA, it’s possible that your 2FA codes are failing to deliver.

Or, if you use SMS for two-way marketing conversations, tracking replies will help you determine if your SMS system is reliably delivering every message.

Essentially, it’s important to track key performance metrics and watch for anomalies that indicate your messages are not being delivered, rather than being delivered but not getting the response you want.

SMS delivery is important. If you follow marketing and delivery best practices and work with an SMS provider that operates a reliable and secure network, you should get near-perfect delivery rates.

Maximize SMS delivery with Telnyx

Looking for a carrier that will help you get those near-perfect SMS delivery rates? Get in touch with a Telnyx expert to learn more about SMS messaging on the Telnyx network.

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