SMS Delivery: The formula to reach a 99% delivery rate

Engaging with your users is an important first step, but it’s equally crucial to ensure that your messages are actually reaching them. That’s where SMS delivery rate becomes essential. This key performance indicator (KPI) helps you measure the number of recipients who actually receive your messages.

So, what is a good delivery rate? How can you enhance it? And is there a more insightful KPI to track? (Hint: There is.)

What is SMS delivery?

SMS delivery is the process of successfully sending a text message from a send to a recipient’s mobile device via Short Message Service.

In the context of business messaging (companies sending SMS to users), SMS delivery (or deliverability) also refers as a metric used to assess the success of a SMS campaign.

Similar to email delivery rates, it keeps track of the volume of targeted users that actually received the SMS.

The SMS delivery rate is calculated as such:

Messages delivered / Messages sent = SMS delivery rate

What is a good SMS delivery rate?

A SMS delivery rate can be considered good when it falls between 95% and 98%. This means that the vast majority of your audience has received the message.

Why not 100%?

Reaching a perfect 100% delivery rate is nearly impossible due to various technical factors that can affect message delivery.

What if your rate is below 95%?

A delivery rate below 95% could indicate underlying issues, such as network problems, carrier filtering due to content violations, or a high number of invalid phone numbers in your database.

Can you aim for 99%?

You might be wondering if a 99% or even 99.9% delivery rate is achievable. While some sources suggest these rates are unrealistic due to the many variables involved, we believe it's possible with the right approach. Keep reading as we share our proven strategies that help our clients consistently achieve top-tier delivery rates.

Why is SMS delivery important?

SMS is a versatile channel for various marketing purposes, but it’s particularly crucial for delivering important notifications such as transactional and verification messages.

When these messages suffer from poor delivery rates, significant issues can arise. Users might miss critical information or face barriers accessing your app, leading to frustration and potential disengagement.

This challenge is what drove Bitstack, a fintech app offering a crypto wallet, to partner with Prelude.

Previously, Bitstack relied on Firebase and Twilio, who worked fine in a few supported countries. But outside of this list of countries, deliverability was not reliable and Bitstack had no or little ways to see if the SMS was really delivered or not. When confirming a payment or a transfer, failing to receive an SMS adds unnecessary stress to already high-stakes transactions.

A low delivery rate not only affects user satisfaction but can also disrupt your growth strategy by breaking viral loops, such as invitations and referrals.

What can negatively impact your delivery rate?

SMS delivery failures can happen due to various factors. Here are the most common ones:

Incorrect or invalid phone numbers

Messages will fail to deliver if the recipient’s phone number is outdated, incorrectly formatted, or invalid—often due to users accidentally entering the wrong number.

Carrier filters

Carriers automatically filter messages that contain content perceived as prohibited, fraudulent, or spammy.

Recipient’s phone issues

Sometimes it's not your fault, but your users'. If their phone is turned off, out of service range, or has storage issues, messages may not be delivered, at least temporarily.

Technical issues with SMS gateways

Delivery can be disrupted if your SMS provider experiences server downtime, technical glitches, or misconfigured routes.

Using grey routes

Grey routes are unauthorized, lower-cost pathways that bypass standard billing channels by exploiting weaknesses in international SMS traffic. While cheaper, these routes are unreliable and often result in inconsistent or failed message delivery.

Short code or sender ID restrictions

Carriers frequently require short codes and sender IDs to be registered and approved before use. These requirements vary by country, with strict rules governing who can use them and how they must be formatted. Messages from unregistered or unauthorized codes are typically blocked to prevent spam and protect users.

How to improve your SMS delivery rate?

Now it's time to reveal our secret formula and explain how to achieve a 99% delivery rate (or even 99.9%, as some of our customers do).

1. Choose the right SMS service provider

Your SMS provider plays a major role in your delivery rate. You need to make sure of its reliability. When looking for a new provider, ask them for their delivery rate, time, conversion rate and prices.

Additionally, check for compliance certifications as a sign of reliability. For example, many enterprise companies require their providers to be SOC 2 Type II compliant, which demonstrates adherence to rigorous security and operational standards.

2. Use multiple routes

When a company deals with a large number of users in many countries, the traditional approach of using a single supplier is not enough to guarantee both the best delivery rate and the best cost. This is where multi-routing comes into play.

Multi-routing involves distributing your SMS traffic through multiple providers rather than depending on just one. This approach mitigates risks associated with provider downtime or deliverability issues by redirecting traffic to alternative providers if problems arise, ensuring uninterrupted service.

But manually adding new suppliers and negotiating rates with each of them becomes unmanageable as the business grows. Outsourcing this task to a multi-carrier provider simplifies the process.

For example, Prelude connects you with 30 global carriers, optimizing routes to balance cost and delivery efficiency. This integration allows you to streamline your SMS operations with a single point of contact, saving time on both implementation and day-to-day supplier management.

For each number you need to send an SMS to, we arbitrate among all our providers, checking a variety of parameters like operator, IP or route performance, to select the route that offers the best conversion to price ratio.

And if the delivery fails, our instant fallback to the next best route ensures near-perfect delivery rates with no downtime. If the door is closed, we open the window to make sure your user converts.

3. Extend to multiple channels

SMS is not the only way to reach your users. Opening new channels to your delivery system is a great way to improve your deliverability.

Online messaging channels such as WhatsApp, RCS or Viber are cheaper than SMS and can be as efficient if used on the right person at the right time.

For example, if your user is in an area with poor cellular network coverage in Brazil, your OTP could be delivered through WhatsApp rather than SMS to deliver the OTP as this channel is known to be more likely to reach the user in this country.

How can Prelude help?

Our API's multi-route system automatically selects the most efficient channel to reach users individually. With no fixed fees on SMS pricing, our unbiased approach reduces costs and achieves an average 95% conversion rate for clients.

This routing strategy, combined with maintaining a clean and accurate database and ensuring your message avoids any spam-like content, will significantly enhance your delivery success!

To wrap up Bitstack's story, partnering with Prelude led them to a 99.8% delivery rate and 95% conversion rate. It was a 10 points improvement globally compared to competitors and even higher in regions that were inadequately supported by the two other providers. By reducing the number of attempts, we also lowered the cost of their SMS verification service.

Going beyond SMS delivery

While tracking SMS delivery rates is useful, it’s not the ultimate metric to focus on. The real goal is to measure conversion: how many recipients actually took the desired action as a result of receiving your SMS?

Let’s take the example of a business that sends SMS to verify the identity of new users.

Focusing on delivery rate will only capture only the initial step of the authentication process—whether the verification code was sent or not.

However, this overlooks the crucial next step: user conversion.

Conversion rate offers a more comprehensive view. It tracks how many customers successfully used the verification code, providing insights into those who don’t convert and why.

By enabling our users to monitor this strategic KPI, we’ve helped them achieve an average global conversion rate of 95% for their SMS verification strategy. Some users have even seen a 3x increase in conversion rates compared to their previous providers!

So, which KPI will you focus on next?

If you’re interested in tracking your conversion rate, you can try Prelude for free or talk to our sales team!