Understanding SMS deliverability and best practices

1. Your phone number

The type of phone number you use may affect your SMS deliverability. Some of the most common options include:

• Toll-free numbers: Toll-free numbers are 10-digit numbers that begin with an 8XX prefix and are only available in the US and Canada. These numbers need to be verified, which may take around 7–10 days to process.
• Dedicated short codes: Short codes are typically 5–6 digits. Brands must apply to get a short code, which takes time. But because of this process, short codes are more trusted by wireless carriers. Short codes are a good option for brands that want to avoid heavy filtering or want to send more than 30,000 messages at once.

• Long codes: Long codes are country-specific. For example, if you have an Australian long code, you can’t send messages to anyone in Ireland. One of the benefits of long codes is that they allow you to receive inbound messages. Long codes have to be verified in Australia and Ireland, which may take 1–3 business days to complete.
• Branded sender IDs: With branded sender IDs, you can set your brand’s name as the sender ID or number when you send one-way text messages. The same branded ID can be used across countries. There is a registration process for branded sender IDs in Australia, which takes 7–10 days to complete.

2. The content and quality of your messaging

There are various levels of filtering in the ecosystem to ensure that only messages that are appropriate and desired arrive on a wireless subscriber’s handset.

For instance, carriers will typically check the content of a message for any non-compliant terms—specifically those related to sex, hate, alcohol, firearms, or tobacco (SHAFT), as well as federally illegal activity or substances, like cannabis.

A history of poor performance with your audience can also lead to filtering or suspension of your sending number. If the recipients of your messages are opting out at a high percentage, or report your messages as SPAM, this can impact your ability to send.

3. The recipient’s mobile device

Once the wireless carrier approves, the message should arrive to the individual’s phone. But there are times when a text cannot be delivered.

For instance, if the recipient’s phone is off, in a location without service, out of credits, or no longer in service, your message may fail to deliver. Certain devices, such as Androids, can also filter messages into a spam folder.

As you can see, there are many factors that can affect SMS deliverability. So how do you make sure that your overall SMS performance is healthy and moving in the right direction?

Strike the right balance in timing and frequency

One of the challenges with any form of omnichannel marketing is figuring out how to send the right number of messages at the right times.

You want to find the right balance when texting your SMS list. Regular sends keep your brand top of mind, but sending too frequently can cause fatigue and increase opt-outs, especially if your messages aren’t personalized. The goal is to stay engaged with your audience without overwhelming them.

Even the most seasoned SMS marketers benefit from keeping these cadence best practices top of mind:

• For SMS flows, keep SMS and MMS quiet hours enabled. This is generally any time before 9 a.m. or after 8 p.m. in the recipient’s time zone.
• Aim to send at least 1–2 SMS campaigns per week to regularly engage subscribers.

• If you use Klaviyo, take advantage of Smart Sending, which lets you control the number of emails, SMS messages, or push notifications someone can receive within a set period of time.

Focus on segmentation

When setting up SMS campaigns, use segmentation to your advantage. Here are two SMS segments we recommend focusing on to improve deliverability:

1. Error segment: As we mentioned earlier, an error segment excludes SMS subscribers who are unable to receive your messages. By excluding this demographic, you can increase your deliverability and avoid wasting SMS credits on people who aren’t likely to receive your messages.
2. Unengaged segment: This segment definition may vary from business to business, as what “unengaged” means strongly depends on how often a business sends SMS and their typical buying cycle. But for someone sending weekly, a typical unengaged segment may include those who haven’t clicked an SMS and didn’t visit your website in the last couple of months. We recommend sending to your unengaged segment at least once a month.

By strategically using segments in your SMS campaigns, you can improve deliverability while ensuring your subscribers are only receiving the messages that they actually want to see from your brand.

Invest in the right platform

Choosing the right marketing platform can have a significant impact on your SMS deliverability. Plus, the best platforms serve multiple functions.

First, the top SMS platforms bake compliance and deliverability features right into their technology. They also surface critical information that removes the guesswork for your team—saving you valuable time and resources—so you can understand exactly what changes you may need to make to future messages.

Klaviyo, for instance, shares the deliverability rate for each text message you send, as well as insights into why individual messages weren’t delivered. We also recommend choosing a platform that bundles SMS and email under one roof. This empowers you to see how your customers are interacting with both of these channels, all in one place.

It also helps you make smarter marketing decisions, such as sending messages to your customers through the channels they prefer or creating a more seamless omnichannel experience.