Smart start: Beginner's guide to SMS deliverability

Travis Hazlewood

· Sep 18, 2024

If you’re new to SMS marketing, welcome.

If you’re not new but came here because things are already a cluster for your messages, welcome to you too.

As you may (or may not) know, my deliverability expertise has primarily lain in email for over 5 years now.

Over the last few years though, I have added SMS deliverability to my skill set and knowledge base, thinking it shouldn’t be too hard of an addition.

I quickly learned that is not the case at all.

While I have a leg up due to the required troubleshooting skills being similar, the actual knowledge and requirements involved are completely different and much more complex. (There are even a couple of best practices that are opposite for SMS than in email!)

Essentially, what I’ve learned is that SMS marketing is a wholly separate skill set and requires much more effort to implement at the beginning than email marketing.

No, I don’t want to turn you away from SMS as a marketing tool.

It is a high-impact tool that can provide visibility and immediacy in a way that email can’t.

But that’s only if you can get your messages delivered at all.

First, we need to break some misunderstandings you may have about SMS based on your email experience.

Biggest ways SMS deliverability differs from email

SMS has much stricter legal requirements

What country you’re sending to, what content you are sending, how you are acquiring permission, and even what time of day you are sending are all examples of things that can have legal limitations for your SMS traffic.

To understand what can affect your traffic, you will want to review the per-country regulations of your audience, which you can do here.

SMS has more bespoke limitations affecting deliverability

Each country and carrier within that country has its own limits on the types of sending numbers accepted, speed of delivery, and more.

Thankfully, these resources should be helpful in understanding both your legal and deliverability-related limitations with SMS.

Just know it is not light reading and there are various registration processes to undergo in different number use cases so you will want to know your desired strategy with SMS to see what limitations you will need to work with.

SMS has stronger and higher engagement rates

Here is the protein of what makes SMS such a valuable channel.

According to Twilio, “The typical open rate for SMS is 98% and in general, marketing messages have an average open rate of 82%.”

And while I have seen general email marketers struggle to get their email campaign click rate averages above 2%, the ideal SMS click rate average is above 7%.

The reason for this is quite simple: SMS is way more invasive than email.

You might think that’s an all-around win, but it also means that over-sending can easily and quickly not only lose you subscribers en-masse but can also earn you junk filtering with providers much faster …and junk filtering in SMS can be harsher than spam filtering in email.

SMS has a more difficult remediation process for deliverability issues

Some SMS delivery issues are easy to troubleshoot and resolve based on their bounce reasons, but many, especially those related to junk filtering, can be an outright pain to troubleshoot, let alone resolve.

If you are lucky, the provider will bounce your SMS messages due to junk reporting from recipients.

However, some do not and lean on spam filtering, which in the SMS space is to simply “blackhole” the message. (This is where the carrier accepts the message but then simply drops it into the void instead of passing it on to the recipient’s device.)

The only signs of this are a sudden drop in clicks (if you are using that in your strategy) or recipients reaching out to your organization advising of missing messages.

In all of the cases above, you will have to work with your trusted SMS provider to get with the related carriers and understand the changes you will need to enact to resolve the issue…if they even let you.

It’s doable in most cases to resolve but, as usual, it is best to avoid being listed as a spammer with your SMS at all than to have to try to resolve this.

And a few more things...

There are other more minor differences, like character length for example, but for the sake of brevity we will end this section here.

SMS best practices for good deliverability

Now that you’re good and properly scared (sorry about that), let’s dive into how you can set things up right from the start to be able to enjoy the benefits of SMS marketing.

Identify the role of SMS in your marketing strategy

Your SMS strategy should be in alignment and support of your other channel efforts, rather than used as the main channel itself.

How can SMS support your current efforts, filling in the gaps and using its ability to gain immediate attention in a way that is desirable and helpful from the recipients’ perspective?

In the end, if you don’t know what to do, start by using it as a transactional and customer support channel before testing the waters with promotional communications.

Identify your audience locations and review country-specific delivery limitations

If you are limited to a single country, then this can be easier, but regardless of whether this is the case or your brand is international, you will need to know all of the limitations and registration requirements before you try to move forward with picking a sending number, let alone sending at all.

Select the ideal number(s) for your needs

A single US phone number can sometimes be enough to get SMS delivered across multiple countries, which will save you from having to register in all the various countries (and save you money), but there are limitations that you need to be aware of when trying to send internationally.

On top of this, even if you are sending within a single country, there are different types of SMS sender IDs —like short code, long code, toll-free, etc.— that each has benefits and losses to consider, from pricing to speed.

Knowing what you need and your financial resources around this can help you quickly understand the ideal sending number solution.

Build out a clear and unforced opt-in process

All SMS opt-in forms should include:

Transparent outline of content being opted into
Have its opt-in defaulted unchecked
Have a separate checkbox for opting into marketing content
Include links to Privacy Policy and Terms and Conditions

Clearly communicate unsubscribe instructions

In both the Terms and Conditions and with the first message after opt-in, you need to clearly outline the subscribers’ options for unsubscribing.

Use a short custom domain for click-tracking

Using a shared domain for links in SMS content can easily get your SMS traffic blocked or filtered due to the traffic of other SMS senders using that domain, much more so than in email.

You will want to utilize a custom tracking domain that protects your traffic from deliverability issues that could be shared with a shared tracking domain.

Don’t forget to keep it short to protect your character length limitations with SMS.

Be highly intentional with your frequency and content types

Since SMS is so invasive, it is even more important for this channel than any other channel to only send desired and relevant content.

Transactional and support-related content is especially ideal for this channel, but your promotional frequency should be at least halved with SMS than email, and content should be even more hyper-personalized/targeted. (No spray and pray techniques with SMS)

Maintain strong engagement metrics

As with email, understand what healthy engagement stats should look like with your SMS traffic and work to regularly improve to keep your reputation healthy.