Getting Started with Klaviyo SMS and MMS

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SMS stands for "short messaging service," and SMS messages may more commonly be referred to as text messages. SMS marketing is a broad term and covers two types of text messages: SMS and MMS. MMS stands for "multimedia messaging service" and enables you to attach images and GIFs to your messages. 

SMS and MMS messages are the most widely used type of mobile messaging. Klaviyo's tools allow you to centralize your marketing strategy into one platform and expand your reach beyond the inbox. Using customer data, like preferences and behaviors, you can achieve true personalization of every message you send, driving more clicks and conversions.

Currently, SMS and MMS messages in Klaviyo can only be sent to U.S. numbers and you can only collect SMS consent from U.S. phone numbers. You cannot collect consent from/send texts to Canada, Puerto Rico, or other numbers.

Whether you're looking to start an SMS strategy from scratch or already have a clear vision for how you're going to use SMS to nurture relationships with your customers, there are several key steps that you'll need to take to get set up with Klaviyo.


Before you get started, be sure to review our compliance requirements for sending SMS messages. There are eight key steps to getting started with SMS that will be outlined in more detail in this guide, including:

  1. Set up SMS messaging in your account settings
  2. Choose your SMS number
  3. Choose your SMS plan
  4. Update your terms of service
  5. Gather SMS subscribers
  6. Add SMS messages to your flows, or create a new SMS flow
  7. Create and send an SMS campaign
  8. Analyze how your SMS messages are performing and iterate

Set Up SMS Messaging in Your Account Settings

Once you've decided you'd like to use Klaviyo to send SMS messages, the first step to getting set up is to configure this option in your account. You can do this by heading to Account > Settings > SMS. Then, click Set Up SMS. Only account Owners and Admins will have this ability. Also, you must set up SMS before you can begin collecting consent when double opt-in is enabled.

Note: You must have SMS enabled before you can begin collecting SMS and MMS consent. 


Learn more about fully configuring SMS in your account, including adjusting your Smart Sending and conversion windows, which are set to 24 hours by default.

Choose Your SMS Number

When you add SMS to your account, you will automatically be assigned a free phone number from which outgoing SMS messages will be sent to your subscribers. If you would like, you can add new numbers by clicking Additional Numbers > Request Additional Numbers

Please note that, if you request a short code or wish to port over an existing SMS number, Klaviyo must approve your request before you can begin sending from the new number(s). When requesting additional SMS numbers, you will have several options:

  • Long number (e.g., 1-XXX-XXX-XXXX)
  • Toll-free number (e.g., 1-800-XXX-XXXX)
  • Short code (e.g., XXX-XX)
  • Vanity short code (e.g., XXX-XX)

Learn more about the pros and cons of each of these options in our guide to choosing your SMS number.

If you are coming over from a previous SMS provider and already have a number, you may instead select Additional Numbers > Port an Existing Number. You can port over long numbers, toll-free numbers, as well as short codes. 

Choose Your SMS Plan

You can select an SMS plan by going to Account > Billing > SMS Plans.


Please note that billing for SMS operates differently than billing for email. To start, you will receive 50 free messages, and can then select a plan from here.

Learn more about how you're billed for SMS messages and selecting an SMS plan.

Update Your Terms of Service 

Before you start collecting SMS and MMS subscribers, you want to make sure you also update your terms of service as well as any other publicly facing legal document you have (e.g., your privacy policy). Head to this article to see a sample SMS terms of service

Collect SMS Subscribers

You must get explicit consent from your customers before sending them SMS messages — even transactional ones. So even if you have phone numbers in your Klaviyo account, this does not mean you can send to them.

Further, SMS consent is different from email consent. When gathering SMS consent, you must have language that clearly indicates that if someone ops in, they agree to receive SMS marketing from your brand at the number they provided. 

There are several ways to either collect or sync SMS consent into Klaviyo: 


Send SMS Campaigns

A campaign is helps you provide value to your SMS subscribers.  Using an SMS campaign, you could:

  • Inform subscribers about a flash sale
  • Notify them of a product launch

When creating campaign messages, keep the following points in mind:

  • Make sure recipients understand who the message is coming from (such as by mentioning your brand's name)
  • Always include opt-out language
  • Do not use any words related to sex, hate, alcohol, firearms, or tobacco
  • Do not mention locally or federally illegal substances, including CBD, in the text or URL
  • Keep the message concise
  • Send only between the hours of 9 am and 9 pm in the recipient's local time
  • Include a link

Find out more about creating SMS campaigns.

Use SMS Messages in Flows

Using flows, you can create several key customer experiences, including:

Most of the best practices for campaigns applies to flows: don't use SHAFT or illegal terms, include opt-out language, keep it concise, have a link, and clearly indicate who the message is coming from. 

Learn more about how you can use flows to send SMS messages to your subscribers.

Analyze SMS Performance

Once you have an SMS strategy up and running, the next step is reviewing your analytics and iterating accordingly.

Learn the key metrics to keep an eye on when reviewing your SMS messages, as well as about some ideas for testing in our guide to analyzing and understanding SMS performance.


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