Messaging • Last Updated 4/30/2024

SMS Delivery: Maximizing Efficiency and Reach

Maximize your SMS marketing with our SMS deliverability guide. From measuring to optimizing delivery rates, we've got you covered.


By Emily Bowen

Successful SMS delivery image

Imagine crafting the perfect text message for your SMS marketing campaign only to discover it never reached your audience. Frustrating, isn't it? This obstacle is where SMS deliverability comes into play.

Simply put, you can’t execute a successful SMS campaign by sending messages into the void. You also have to ensure they get read. Any undelivered message counts as a missed opportunity. Since tracking deliverability is crucial, having an SMS platform that offers detailed deliverability reports can be a game-changer for businesses and marketers.

In this post, we’ll unravel the mystery of SMS delivery, explore its significance, and arm you with strategies to turbocharge your text message deliverability.

Understanding SMS delivery and why it matters

Your SMS delivery rate is a measure of how many messages were successfully sent to their intended recipients. It is expressed as a percentage of the total number of messages you sent. So if you sent 100 messages and 80 of them were delivered, your delivery rate is 80%

Understanding SMS delivery is important because it affects your SMS marketing performance. Knowing your delivery rate helps you avoid misdiagnosing why your SMS marketing could be underperforming. It also enables you to assess the more technical aspects of your SMS campaigns.

For example, if your delivery rate is high but your SMS marketing isn’t performing well, the issue likely lies with your message content, sending time, call to action, or something related to marketing fundamentals. 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 worth noting that your SMS delivery data won’t tell you when you’ve sent a message to the wrong person. It just tells you whether a message was successfully delivered to a device. If the wrong person reads the message because it was sent to the wrong device, they’ll probably opt out of your campaign.

Ultimately, SMS deliverability matters because even if you don’t have to pay for undelivered SMS messages, they represent missed opportunities. Knowing your SMS delivery rate enables you to optimize your conversion rate. When you dig into the metrics behind your messages, you can get more bang for your buck by creating engaging messages that actually reach their recipients.

How SMS delivery reporting works

Digging into SMS metrics requires a basic understanding of how to read your reports. Let’s talk about how delivery reporting works and the information you might find in a thorough report.

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 it has received the message. This counts as a delivered message.
  2. The message never reaches its intended destination, and your SMS carrier’s servers attempt to collect information about why it wasn’t delivered.

This information collected by the carrier is called an error code. Fortunately, you can quickly resolve most error codes by checking the phone number, network connection, or message content. Here are the top four codes our customers ask about and what they mean:

40001Not routable (destination number is a landline or a non-routable wireless number)
40012Invalid messaging destination number (the destination phone number was deemed invalid by the carrier and was rejected)
40002Blocked as spam
40018 or 4001610DLC sending limit reached: exceeded throughput limits for allocated use case

For more information about error codes, check out this video from our Messaging team:

Understanding how SMS delivery reporting works is crucial for optimizing your SMS marketing campaigns. You can gain valuable insights into your SMS delivery performance by knowing the different outcomes of an SMS message—whether it's delivered, opted-out, or undelivered due to a soft or hard bounce.

This knowledge allows you to identify potential issues, make necessary adjustments, and improve your SMS deliverability. Remember, a successful SMS marketing campaign is not just about crafting the perfect message but also ensuring your message reaches its intended recipient.

Common reasons for undelivered SMS

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 an unassigned phone number, which is different than having the wrong phone number. If you have the wrong number, your message can still be delivered—just to the wrong person. However, messages to an invalid number are never received by anyone.

Your carrier uses gray routes

Gray routes are message delivery routes that use unauthorized networks to avoid paying third-party network operators for transmitting a message.

Spam filters stopped your message

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

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.

All these issues can produce different sorts of delivery problems. But the bottom line is that an SMS message that encounters any of the problems outlined above won’t be delivered.

Tips to improve SMS delivery rates

The good news is that you have control over any delivery issues that occur on your end. Phone numbers and message quality are problems your team can easily correct. Here’s what you can do to improve your delivery rates:

Quality control your phone lists

People often make mistakes when they enter their phone numbers in contact forms. They can also change their phone numbers between the time they gave it to you and the time you send your first campaign message. Regardless of why a phone number might be wrong, you need to validate the phone numbers in your CRM databases to eliminate invalid numbers that drive delivery rates down.

One effective way to ensure the validity of your phone numbers is by using a phone number lookup feature like Telnyx's Number Lookup API. This tool provides detailed information about each phone number, including the carrier information and whether the number is a landline or mobile.

Using such a feature allows you to differentiate between landline and mobile numbers programmatically and check carrier information to guarantee message deliverability. This information can significantly improve your SMS delivery rates by ensuring you’re sending messages to valid, active numbers.

Include opt-out instructions

Failing to include opt-out instructions is a violation of most SMS regulations and 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. A keyword opt-in also ensures 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 you should switch to a new SMS provider, preferably one that owns a private network.

For more tips on maximizing your deliverability, follow these operational tips from our Messaging team:

Top 3 metrics to monitor

As you begin to assess your SMS deliverability rates, it's crucial to keep certain metrics at the forefront of our analysis. Here are three you should pay close attention to.

1. DLR (delivery receipt) ratio

The DLR ratio is the number of messages that receive a delivery status (delivered or undelivered) measured as a ratio against the total number of messages sent.

Generally, a high DLR ratio is good, but a consistent DLR ratio is more important. 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.

2. Delivery latency

An SMS delivery status should come with delivery latency information that shows how long it took to deliver the message.

Like your DLR ratio, the absolute number isn’t as significant as its consistency. Wide variations in delivery latency can indicate potential issues in your carrier’s SMS delivery infrastructure. Wide variability doesn’t necessarily mean your carrier is bad. But more consistent delivery latencies indicate more stable SMS infrastructure and fewer network hops, which means more security.

3. Case-specific metrics

It’s also important to track the metrics that tell you whether or not your SMS messages are performing as intended, which can differ based on your SMS campaign strategies and processes.

For example, if you’re using SMS for two-factor authentication (2FA), you should track successful logins and alternate authentication uses. If users must frequently opt to receive an email for their 2FA, your 2FA codes may be failing to deliver. Or, if you use SMS for two-way marketing conversations, tracking replies will help determine if your SMS system reliably delivers every message.

Essentially, it’s important to track key performance metrics and watch for anomalies that indicate your messages aren’t haven’t been delivered rather than being delivered but not getting the response you want. By monitoring these metrics, you can ensure your SMS delivery is performing at its best and identify areas for improvement.

Achieve maximum SMS deliverability with Telnyx

In this post we've explored the importance of SMS delivery rates, common reasons for undelivered SMS, and strategies to improve these rates. Optimizing SMS delivery is vital as it directly impacts your marketing campaign's success, ensuring your messages reach the intended recipients and increasing chances of engagement and conversion. Monitoring key metrics like DLR ratio, delivery latency, and case-specific metrics is crucial to assess performance and identify areas for improvement.

Telnyx's SMS API provides the tools and support you need to implement efficient messaging campaigns and achieve better performance. Our adaptive routing feature analyzes message delivery rates and automatically adjusts the route for optimal deliverability. This feature means your messages are more likely to reach their intended recipients, resulting in higher engagement and conversion rates.

In addition, Telnyx provides analytics and insights tools, including a Messaging Deliverability Dashboard, that offer valuable data on your messaging campaigns. You can leverage these insights to make data-driven decisions that improve your messaging strategy, fine-tune your message content, delivery times, and targeting, maximizing the effectiveness of your SMS campaigns.

Whether you're a budding startup or an established enterprise, SMS can help you forge meaningful connections with your customers and drive business growth. Our API supports SMS, MMS, 10DLC, Toll-Free numbers, short codes, and more.

Talk to a Telnyx expert to learn how we can help you elevate your messaging capabilities for enhanced customer engagement, more efficient communication, and a significant boost to your business growth.

Want more information on how to ensure your messages are delivered? Check out these other resources:

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