Guide to Crafting SMS and MMS Messages

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After you’ve set up SMS messaging in your campaigns and flows, you can start building out your SMS messages. This article will run through creating an SMS message in Klaviyo, configuring the content, and some best practices for text messages.

Check out our guide to Getting Started with SMS for step-by-step instructions on how to start using SMS. 

Adding an SMS Message

Before you start creating and sending SMS messages in Klaviyo, you need to enable SMS on your account. For instructions on how to do so, read Set Up SMS.

Create SMS content by clicking a specific flow or campaign name. For SMS campaigns, choose the name and recipients and then navigate to the Content step.


For flows, drag in an SMS component and select Configure Content.


Building Out Your SMS Message

When crafting your message, there are two main things you want to be conscious of: the content itself (your tone, CTA, link, etc.) and any relevant compliance laws. 

Crafting Your Message

You only have a matter of seconds to make an impression on your recipients, so keep your message short.

  • SMS messages are limited to 160 text characters or 70 with any special characters (e.g., ~, &, and é)
  • MMS messages can have up to 1600 characters and the media must be in one of the following formats:
    • PNG
    • JPEG
    • GIF

Note that emojis and symbols (e.g., © and ™) count toward the character count. Further, the character count for shortened links and dynamic content varies, so be mindful not to get too close to the 160 or 1600 character limits.  

That being said, in general, try to write in full sentences and don’t use abbreviations. While it may be tempting to use texting abbreviations to keep your text short, your abbreviations may not be apparent to the recipient and could make your brand appear unprofessional. If you have a very specific brand tone and a customer base that you feel confident will understand your abbreviations, it's fine to use them sparingly. 

You can personalize your message by using any of the properties in the Add Property dropdown, which shows all of the template variables available in Klaviyo. Using this, you can, for example, address the recipient by their first name, if it's known. If it's not, you can use a generic term, such as "friend."


You can also use GIFs and static and dynamic images in your texts. Simply click Add Image/GIF and choose your media. Note that when you add an image or GIF, the message becomes an MMS, which counts as three credits. For more details on using graphics, check out MMS Image and GIF Best Practices.

Including a Link

As a best practice, always include a link in your SMS messages and use Klaviyo's link shortener.

A key metric for SMS is click rate, as almost all SMS messages are opened. If there's no link in the message or the link is not shortened, you won't have insight into how your SMS and MMS messages are performing, as Klaviyo won't be able to track the messages. Shortened links are typically 24–25 characters, but this can vary. 

If you want iOS 10+ users to see a preview of your link, you need to do two things: 

  • Include http:// or https:// at the start of the link
  • Place the link at the very beginning or end of the message

Note that for this to work, the link cannot be followed by any other text (including opt-out language). Further, this only works when there is only one link per message. 

Being Mindful of Compliance

After you choose your message, navigate to the Compliance tab. All options are enabled by default. They will apply only to recipients in the countries listed below the option, and are considered to be the best practice for those areas. The options are: 

  • Organization prefix (US)
  • Company info link (Canada)
  • Unsubscribe instructions (US and Canada)
  • Unsubscribe link (UK and Australia)

Note that either unsubscribe instructions or a link are typically required, depending on the recipient's location. 

Viewing Your Message as a Certain Recipient

As you begin creating your message, you'll see how the message will look once it's delivered to a certain recipient in a specific country. This recipient and country are shown in the card in the upper right-hand corner. For list- and segment-triggered flows, you can search for any profile in your account or select from the 10 most recent profiles added to the list or segment.  

Date property-based flows are similar except that they will only show a profile that has the date property that triggers the flow.

When it comes to metric-triggered flows, the card will show the 10 most recent events for the flow's trigger along with the associated event variables. Like with the profile properties, you can simply click on one of the variables to copy it to your clipboard. 


Best Practices

SMS messaging is a great point of contact with your customers, allowing you to remain at the front of their minds. When you’re configuring your message in Klaviyo, it’s important that you adhere to the following tips to get the most out of your SMS marketing.


First, you need to have the proper permission to text someone. Make sure you’ve obtained a customer’s phone number from a legal source (i.e., signup form, in-person event, opt-in on a checkout page). Klaviyo will never send an SMS to a profile that doesn’t have consent. For more information head to the article on How to Collect SMS Consent.


It’s best practice to text a single SMS recipient anywhere from two to six times a month. Like your emails, you’ll want to make sure that you stick to a regular schedule when sending out your SMS messages. Additionally, create a customer journey for someone who signs up for your welcome series or abandons a cart, and figure out how often you’re communicating with that person. You don’t want to communicate too little or too much with a customer. Anywhere between two and six messages a month is a good cadence to start.

Time of Day

As you send out your texts, you’ll want to send them between 9 a.m. and 8 p.m. in the recipient's local time. Most likely, sending an SMS too early in the morning or too late at night will lead to fewer conversions and more people unsubscribing from communication with you.  

For flows, there are quiet hours, which restrict the times when SMS messages can go out based on the country code for the recipient's phone number. For campaigns, you must segment your subscribers by country and be conscious of their local time. 

Test when your recipients like to hear from you. For instance, many ecommerce businesses find that sending around noon on Sunday leads to better performance. 

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