How to Improve Your SMS Delivery Rate and Why It Matters

When an SMS campaign underperforms, you might start doubting the copy, timing, or maybe even your segmentation strategy. But one critical question often goes unasked: did the message even reach the recipient?

Making sure every one of your SMS messages reaches its intended recipient is more important than most businesses realize. Undelivered messages can not only ruin your campaign metrics but also cost you customers and directly impact your revenue. And yet, delivery issues often go unnoticed until much later, when the damage has already been done.

In this article, we’ll break down why delivery rates matter, why SMS delivery fails sometimes, how it affects your performance, and how you can improve SMS deliverability with the right tools and practices.

What is SMS delivery rate?

SMS delivery rate, sometimes also known as SMS deliverability, is the percentage of SMS messages that actually reach their intended recipients, out of the total number of texts you send out.

Messages “sent” are not the same as those marked “delivered”. An SMS message could be sent from your platform and still never reach the user’s phone due to various delivery issues.

A high SMS delivery rate is a sign that your messaging setup is solid and your messages are reliably reaching their intended audience. It could be indicative of several things, such as a clean contact list and high-quality routing. On the flip side, a low delivery rate means your messages are getting lost. This can lead to lost sign-ups, wasted budget, poor user experience, and ultimately, lost revenue.

Maintaining high deliverability is especially important when it comes to transactional messages like OTPs or order confirmations. Failed deliveries in such cases would halt or slow down the user journey.

Providers like Messente can help you keep delivery rates high by giving you real-time visibility into message delivery statuses, so you can proactively track campaign performance, identify problems, and improve ROI as you go.

Understanding the different SMS delivery statuses

Common terms you should know about

SMS delivery statuses help you track what actually happens to your messages after you hit send. Here are the most common ones you’ll come across.

• Sent means your message was accepted by the SMSC (Short Message Service Center), but it hasn’t yet reached the recipient’s device.

• Delivered is what you want to see. It means the message successfully reached the recipient’s phone.

• Failed means the message couldn’t be delivered due to a permanent issue, like an invalid or deactivated phone number.

• Rejected means the carrier blocked the message before it reached the recipient. This often happens due to content problems or spam filters.

• Expired means the carrier tried to send the message, but the delivery window ran out (usually because the phone was off or out of reach too long) and the message was never delivered.

• Undelivered is the final status for messages that didn’t make it through at all. These usually fall under “Failed” or “Expired”.

• Unknown means no status was returned from the carrier, which could point to deeper routing or infrastructural issues.

Why is it important to understand the different types of delivery statuses?

Knowing what each delivery status means is the only way you can spot what’s working and what might be holding your campaigns back.

SMS delivery statuses can help you diagnose not just technical issues but strategic ones as well. For instance, if you’re seeing a sudden rise in “Expired” SMS messages, it could signal that your campaigns might be going out at the wrong time. Similarly, if you see too many “Rejected” statuses, your content might be inappropriate and thus triggering some sort of filter. A high number of “Unknowns” could mean your provider is using unstable or grey routes, especially if delivery performance varies wildly across countries or carriers.

Understanding delivery statuses also helps you make smarter content decisions. If promotional messages are consistently rejected while transactional ones go through, your marketing copy might need tweaking. Maybe your tone is too aggressive, or you’re overusing short links or emojis.

Overall, being able to comprehend and analyze SMS delivery statuses will allow you, as a product manager or marketer, to get a peek into the insights that you need to adjust your campaigns. With these insights, you can make data-driven decisions on factors such as timing, copy, targeting, and segmentation. Understanding delivery stats is key to optimizing campaign performance and reporting results, especially if you’re running high-volume campaigns.

If you feel like you’re constantly in the dark about persistent delivery issues and your provider is not offering any explanations or support, it may be time to make a switch.

5 common reasons behind failed deliveries

1. Poor contact management

One of the most common reasons for failed SMS delivery is poor contact management.

If your list is full of outdated, deactivated, or invalid numbers, your messages won’t land, literally. You’ll burn through your credits for nothing. The same happens if you have numbers saved with formatting issues, or missing or incorrect country codes. These often result in silent delivery failures. Duplicate numbers across variations of the same campaign can also skew your metrics and inflate costs unnecessarily.

And if you’re still sending messages to users who’ve opted out or are on a DND (Do Not Disturb) list, you risk not just rejections but potential legal trouble, too, due to non-compliance with SMS marketing regulations.

2. Routing issues

Routing issues are another major culprit behind failed SMS deliveries.

Some low-cost providers use unstable or grey routes to cut expenses, which often leads to inconsistent or blocked delivery. If your messages are being sent over non-A2P (Application-to-Person) routes, they’re more likely to get throttled or dropped entirely by carriers.

Another problem arises when you don’t have retries set up. Without an automated re-send or fallback mechanism in place, a failed message just disappears without any second chances.

Country-specific restrictions can also get in the way if you’re not careful. For instance, if you’re not properly registered as a sender or your campaign doesn’t meet local compliance standards, delivery might be blocked before it even begins.

Without proper delivery monitoring, you will never be able to notice or find out what is going wrong with your campaigns.

3. Carrier spam filters

Carrier spam filters are more aggressive than you might think, and they’re a common reason behind failed SMS delivery. If your content raises even a minuscule red flag, your SMS might be blocked before it gets anywhere near the recipient’s phone.

Things like using all caps, spammy language or banned words, or shady or unsecured URLs can easily trigger a filter. Using URL shorteners (e.g., bit.ly or tinyurl) also often leads to rejection, especially in the finance or government sectors, where security filters are tighter.

Sending too many messages too quickly can also be a problem. If you’re sending out 10,000 texts in a minute, for instance, carriers may assume it’s spam traffic and shut it down entirely.

Also, if you don’t include a clear instruction for users to unsubscribe, carriers may reject your message automatically.

4. Platform inefficiencies

Sometimes, the issue isn’t your contact list or your content, but the platform itself. If your provider queues messages for too long before trying to send them, especially during peak times, your delivery rate can take a hit. The same goes for flawed or absent retry logic. If there’s no system in place to reattempt delivery when a user’s device is temporarily unreachable, those messages are simply dropped.

Another red flag is a lack of transparency. If your platform doesn’t show clear delivery statuses or explain why a message failed, it’ll be nearly impossible to troubleshoot or improve your performance.

And then there’s the ever-present issue of fraud. Without proper security systems, your A2P messaging system might fall victim to threats such as AIT (Artificially Inflated Traffic) attacks. That would not only drain your budget but could also trigger carrier-level blocking of legitimate messages due to your clean traffic getting mixed up with spam.

5. Lack of support from your provider

Slow or unhelpful support can make your delivery issues and their devastating consequences even worse. Some big providers in the A2P messaging industry take as long as 14 days just to acknowledge a delivery problem, let alone fully resolve it. And while messages continue to fail, revenue keeps slipping away.

Poor onboarding doesn’t help either. Bad providers can leave you unaware of local compliance laws and leave you to fend for yourself. Without proper support, you’ll also be forced to troubleshoot by yourself, potentially with lots of time-consuming trial-and-error, while your users stay lost in the absence of any communication from your end. That’s not a sustainable way to run any high-volume messaging operation.

Examples of real-world scenarios where SMS delivery issues can hurt your business

Delivery issues aren’t just technical hassles. They have real consequences for your users, your campaigns, and your business. Here are some real-world examples that show how failed messages equal lost opportunities.

• When a sign-up OTP doesn’t get delivered, the user often abandons the registration process entirely, leading to lost revenue right at the start of the customer journey.

• If a promotional campaign sent to 50,000 users only reaches 60% of the intended audience, the low deliverability and reach will lead to a poor return on your marketing investment.

• If an appointment reminder never reaches a customer, they might completely forget about it, leading to a no-show and a wasted time slot.

• Fraudulent AIT traffic can silently drain your SMS credits while preventing legitimate messages from being sent out.

• During high-traffic periods like holidays, support teams may see a spike in tickets. Without clear delivery logs, it would be nearly impossible to trace and resolve issues quickly.

• A bloated contact list full of inactive SIMs can drag down your overall delivery rate, making it harder to evaluate campaign success.

• If a payment OTP fails to reach the user at checkout, the sale may be lost on the spot, directly impacting your revenue.

How to boost your SMS message delivery rate: 6 best practices

Choose a reliable provider

Choosing the right SMS provider isn’t just about getting the lowest price. In fact, cutting corners here can cost you far more in failed deliveries, lost customers, and wasted campaign spend. It’s important to weigh things like platform uptime, route quality, SLAs, and support responsiveness. A reliable provider should offer more than just the tech. They should offer a solution that balances all your needs.

Messente, for example, uses efficient internal routing and supports country-specific traffic registration to help you stay compliant and connected. You get a ready-to-use dashboard with real-time delivery insights, exportable logs, and smart filtering options. Our delivery reporting is transparent, detailed, and easy to act on, with real-time status codes available in both the dashboard and the API logs.

Clean your phone number list regularly

Keeping your contact list clean is one of the easiest ways to boost your SMS delivery rate.

Before sending out a new campaign, run a basic cleanup to filter out invalid numbers, contacts that have opted out, or any data that looks outdated. It’s also worth checking for recycled numbers (i.e., numbers that might have belonged to your customers in the past but have since been assigned to completely different users now) to avoid reaching the wrong audience or getting flagged.

Tools such as Messente’s Number Lookup API can make this process very simple. With our lookup tool, you can verify which numbers are still active and valid. This way, you’re not going to waste your SMS credits on unreachable or irrelevant contacts.

Create quality content

What you say in your message can be just as important as how you send it. The quality of your SMS copy plays a major role in SMS deliverability, especially when it comes to avoiding carrier filters.

Personalizing your messages is an easy first step. If every SMS you send looks exactly the same, carriers may treat it as suspicious bulk traffic. Add some variation where possible, such as by using variable tags for recipient names or other relevant contextual info.

Avoid instant red flags like all caps, shortened URLs, and trigger words like “FREE!!!” or “ACT NOW.” These are known to set off spam filters, particularly in extra-regulated industries.

Every SMS message should also include a clear opt-out instruction, like “Reply STOP to opt out.” Skipping this can lead to auto-rejections. Keep these and other local or global laws in mind when creating content and copy for your SMS campaigns. Otherwise, you risk getting banned or fined.

Set up fallback systems

Setting up fallback systems can make a huge difference, especially for time-sensitive messages like OTPs or alerts.

One smart fix for a low delivery rate is to enable fallback from SMS to Viber or WhatsApp. That way, if a message can’t be delivered via SMS, it still has a chance of reaching the recipient through another channel. Providers like Messente make this easy with an omnichannel API that lets you manage fallback logic across SMS, Viber, and WhatsApp, all within the same setup.

It’s also important to configure retry rules for cases where a message can’t be delivered right away, such as when a recipient’s phone is temporarily offline. Plus, if you’re sending at scale, don’t rely on just one route. Using diverse delivery paths helps prevent bottlenecks and improves your chances of getting messages through, even when traffic spikes.

Put fraud detection systems in place

In order to improve your SMS deliverability rate, you must protect your messaging system from abuse.

The most important thing to keep in mind is that you can’t just set and forget your campaigns. You have to keep an eye on your delivery reports in real time and watch for unusual patterns, such as a sudden increase in requests from a specific IP or an unexpected drop in successful deliveries for a particular region or audience segment. Set up thresholds and alerts so you’re notified when things go off track.

Your provider plays a big role here, too. Messente, for instance, actively flags suspicious delivery patterns and gives you real-time insight into delivery statuses. This is so you can act fast before any serious damage is done. A proactive fraud detection system isn’t just a nice-to-have. It’s a key part of protecting both your delivery rate and your messaging budget.

Stay compliant

Compliance isn’t just about avoiding fines. It directly impacts whether your messages get delivered or not. If you’re found not following local rules, carriers might block your traffic without warning.

Start with the basics. Use proper sender IDs, headers, and pre-approved templates, especially when sending campaigns to regions that are particular about them. Always check if you need to register your traffic with local regulators. In some countries, unregistered traffic simply won’t go through.

It also matters when and how often you’re sending your SMS campaigns. Bothering users with messages at odd hours or too often can quickly cross ethical and legal boundaries, depending on the region. To time your SMS campaigns right, consider using a scheduling tool, such as the one offered by Messente.

Also, don’t ignore the actual words in your messages. Some words or phrases might be fine in one country but could trigger spam filters in another.

A good provider will help you stay ahead of these details, but it’s still your responsibility to stay compliant if you want consistently high and reliable delivery.

Wrapping up: Get exceptional SMS deliverability with Messente

SMS deliverability directly impacts both your ROI and your customer experience, and fixing it isn’t just about having the right tools. It’s about trust, visibility, and reliable support, all of which you should be getting from your SMS messaging provider.

Messente brings all of that together. Through an easy-to-integrate omnichannel API, real-time delivery stats, intelligent routing, and strong carrier connections, we combine flexibility, transparency, and consistent performance. Plus, you’re not stuck for days waiting for support or having to pay any surprise platform fees.

If your OTPs aren’t reaching customers on time or your promotional campaigns are falling flat, it’s time to switch to a provider that actually delivers, literally and figuratively!