The Marketer’s Manual to SMS Compliance and Deliverability

Disclaimer: This guide should not be relied on as legal advice. Klaviyo encourages you to work with your legal counsel to make sure your SMS program is compliant with the laws that apply to it.

When you buy a new car, you can bundle a variety of add-on features that will help you be a better driver and let you make smarter decisions on the road—features like back-up cameras, blind spot detection, and lane departure alert, for example.

But regardless of the extras you tack on, you can be confident of two things: The car will help you avoid dangerous situations that break the rules of the road, and it’ll get you where you need to go. 

Shopping for your first or next SMS platform is similar.

While text messaging can be a powerful marketing channel on its own, like with a new car purchase, there are features and functionalities you can add onto an SMS marketing platform to make it an even more valuable tool to grow your business. 

Say you bundle SMS and email into a single marketing automation platform. You can see how your customers are interacting with both of these channels in one place. This helps you make smarter marketing decisions, like sending messages to your customers through the channels they prefer, while creating a cohesive experience.

What’s more, like the safety standards and performance capabilities of a new car, the top SMS platforms on the market bake compliance and deliverability features right into their technology. They’re something you should care about, but not something you should spend all your time worrying about.  

Your attention should be on growing your SMS audience and creatively communicating with your customers with text and email. So fasten your seatbelt and discover how Klaviyo helps you handle compliance and deliverability must-haves like:

  • List growth compliance 
  • Message compliance 
  • SMS deliverability

Chapter 1: List growth compliance

Once you’ve chosen your new SMS marketing platform, you’ll work on building up a list of subscribers who sign up to receive your text messages. 

But this can’t be a process that you undertake lightly. In the U.S., the Federal Communications Commission (FCC) implements and enforces laws—like the TCPA and CAN-SPAM—that regulate SMS marketing to protect the rights of consumers. That’s a fancy way of saying the government wants to make sure people don’t receive text messages they haven’t directly given consent to get.

In Canada, the law governing commercial electronic messages—which includes email, SMS, and more—is the Canadian Anti-Spam Legislation (CASL). SMS in the European Union (EU) is regulated by the General Data Protection Regulation (GDPR), and SMS in the UK is regulated by the UK General Data Protection Regulation (UK GDPR) and the Public and Electronic Communications Regulations 2003 (PECR). SMS messages in Australia are regulated by the Spam Act 2003 and the Spam Regulations 2021.

It’s imperative, and frankly mandatory, that you grow your SMS subscriber list and send your text messages in a way that’s compliant with applicable laws, industry guidelines, and carrier requirements. If you don’t, you could face hefty fines and complicated lawsuits, which is probably the last thing you need. 

To have peace of mind that you’re growing your list and communicating in a compliant way, you need an SMS marketing platform that takes compliance seriously. 

That way, you can focus on segmenting your audience and brainstorming different ways you can personalize your customer outreach to build strong relationships across all of your owned channels—like email and SMS.


Confidently grow your SMS list, without sacrificing compliance

Compliance can be a tricky topic to navigate, and you shouldn’t be alone left to wrangle with its complexities—your SMS provider should be a true partner that provides the resources and tools to help you comply with the laws that apply to your text messaging program. 

As you begin to build your SMS list, you first need to collect express consent from your subscribers. In the US, this means that your SMS signup forms need to clearly communicate the TCPA and the Cellular Telecommunications Industry Association (CTIA) required opt-in language like:

    • Messages received by your subscribers will be marketing/promotional in nature
    • Messages may be sent via an autodialer
    • The agreement to subscribe is not a condition of any purchase
    • Message frequency (e.g., “Message frequency varies”)
    • “Message and data rates may apply”
    • Link to your brand’s mobile terms and conditions and privacy policy
    • Opt-out and help instructions

Regulations have the right of way:
What you’re required to include on your signup forms as you collect consent differs from country to country. Review what the list growth requirements for Canada, the United Kingdom, and Australia are before sending messages to customers in those regions.

It would be a hassle for you to remember to include each of these points as you try to design eye-catching signup forms, which is why Klaviyo’s SMS signup forms include this language by default.

Klaviyo only supports SMS list growth tactics that gather express consent from each of your subscribers, which means all of your SMS signup forms will automatically include required opt-in language. You can use it as-is or modify it to fit your needs with the help of your legal counsel.

List growth tip:
Any place you’re asking people to join your SMS list besides your website—like physical retail locations, in-person events, or product packaging—share the phone number people can text to sign up for your text messages, along with your dedicated signup keyword (i.e., WELCOME21) and required opt-in language so your potential customers can subscribe in a compliant way.

In the UK and Australia, when using alphanumeric sender IDs, it’s only possible to text one way. This means you can text your customers, but they can’t text you back (or at all).

sms marketing sign up form on a mobile device


klaviyo signup form for text messaging on a desktop

List growth compliance doesn’t just apply to new subscribers who’ve signed up to your SMS list. If you’re importing your existing SMS contacts into Klaviyo, you’ll automatically get a prompt to upload the date that each subscriber consented to receive your SMS messages, along with their phone number. 

That way, you can stay organized from the get-go and you won’t have to worry later on if you have all of your SMS subscribers’ express consent on file.

example of klaviyo help dashboard saving consent on file


More ways to grow your SMS list:

      • Embed a signup form in the footer of your website or on a shopper’s order confirmation page 
      • Use a pop-up to serve a signup form to new website visitors 
      • Use an Instagram swipe up feature
      • Invite your shoppers to sign up for SMS on one of your product detail pages (PDP) and then follow up with specific questions about the products they viewed on your page via text 
      • Send an email to a segment of your email subscribers who haven’t yet signed up to receive your text messages and invite them to do so with a specific call-to-action (CTA)


Another thing you shouldn’t have to fret about? Your SMS platform charging you for compliance-related SMS messages that welcome your new subscribers. 

For example, in the U.S. CTIA guidelines require that you immediately send your new subscribers a reply message that includes your business or program name, STOP instructions, HELP instructions, and the phrase “Msg&Data rates may apply.” 

But if new subscribers are signing up to your list and you’ve already sent all the messages your plan allows for, you may worry that this required message won’t get sent. 

Your SMS plan shouldn’t dictate your ability to keep your business legally compliant and abiding by standard SMS requirements. That’s why Klaviyo automatically pulls your brand name into this message and sends it to all your new SMS subscribers, without charging you for it—because compliance doesn’t have to come at cost.

Want to learn more about how to get started with SMS marketing?

Chapter 2: Message compliance

Staying compliant doesn’t end with building your SMS list. You also have to ensure every text message you send to your subscribers adheres to specific laws and regulations.

Before you send:
The information you’re required to include in your text messages differs from country to country. Review the message requirements for Canada, the United Kingdom, and Australia before you send messages to customers in those regions.

The same way seatbelts and rear-view mirrors help you feel safe and confident as you drive, Klaviyo has some built-in SMS message features to help you stay compliant as you communicate with your audience.


Send compliant text messages

Have you ever been distracted while driving and made a slight mistake on the road? Maybe you forgot to click on your turning signal or you didn’t realize how quickly the car in front of you was braking. 

Features like lane departure alert or an automatic braking system use detection and sensors to correct the minor things you may overlook, and help to prevent a small mistake from becoming a big accident. 

The same idea applies to Klaivyo’s compliance tools. 

Imagine you designed a new promotional text and you accidentally chose to send it to a segment of your audience that contains all your customer profiles, including your customers who haven’t signed up to receive texts. What a nightmare!

One of the most common TCPA violations is sending text messages to people who haven’t subscribed to or who’ve unsubscribed from your SMS list. To help protect against this, Klaviyo’s default setting automatically checks each subscriber profile for up-to-date SMS consent prior to sending your texts and skips any profile that’s not subscribed to your list—phew!

how klaviyo platform skips profiles that aren't consented to text marketing

Another common violation is sending texts to customers who’ve changed cell phone carriers or deactivated their contract. When this happens, that customer’s old phone number could get reassigned to another person—a person who hasn’t opted in to receive texts from you.   

This is an event that’s, as a marketer, hard to keep track of—especially when your SMS list is comprised of tens of thousands of profiles. Klaviyo has a solution. 

When someone ends their cell phone contract or switches mobile carriers, Klaviyo will remove the SMS consent from their profile and automatically unsubscribe them from your list. Customers can easily opt back from their new number.

profile sms information in klaviyo

Once people opt-in to receive your texts, there are a few ways you can not only send compliant messages, but communicate with your audience in a way that builds trust and creates a memorable customer experience.

Include your brand name in every SMS and MMS message

Text is a much more intimate channel than email. If you received a text message from a number you didn’t recognize, you’d probably delete it on the spot, block the number, or ignore the message entirely.   

Your customers want to know who they’re receiving text messages from, which is why Klaviyo allows you to automatically add your brand name to every SMS and MMS message you send.


Pump the brakes:
MMS is not currently available in the UK and Australia because of carrier limits and the use of alphanumeric sender IDs.


By telling your customers, “Hey! It’s me” you can reduce the amount of your subscribers who might mark your messages as spam or who unsubscribe from your content—ensuring you maintain strong deliverability for your engaged subscribers. Plus, you’re required to do so in certain regions like the UK, the EU, and Australia.

Be mindful of when you send texts

Data flows into Klaviyo during all hours of the day, which can trigger SMS automations to send text messages to your customers at inopportune times. 

Bothering your audience with texts while they’re asleep or off the clock can not only lead to higher unsubscribe rates, but it’s also a concern for compliance. Government regulations stipulate you can only send text messages between 9 a.m. and 9 p.m. in the recipient’s time zone. Some individual US states also have additional, stricter mandates.

SMS Quiet Hours is an automatic safeguard that helps you only send texts during business hours—creating a compliant and positive experience for your customers.

Klaviyo will automatically apply this feature to your new and existing campaigns and flows, so you can worry less and send more.

Use clear opt-out language

If it’s difficult for your customers to unsubscribe from your text messages, that could sour their experience and spoil their desire to make a purchase in the future. 

Clear opt-out language, while not legally required in every country, can make a world of difference for your customers. 

Klaviyo recommends including opt-out language in every message you send in the U.S. and providing opt-out instructions at regular intervals and at least once each month. Certain carriers (like T-Mobile) also recommend providing explicit opt-out instructions in every fifth message. 

In other regions like Canada, the UK, the EU, and Australia, you should include opt-out language or an opt-out link (which is required in the UK when using alphanumeric sender IDs) in every message you send.


Try this:
Include opt-out language in a confirmation message, monthly, and other key stages of your customers’ journey—like the second time they make a purchase or their subscriber anniversary.


If your instructions aren’t clear, your subscribers may use their own keywords or language to try and unsubscribe from your content. If that happens, your subscribers wouldn’t be unsubscribed from your SMS list and their profile wouldn’t be suppressed.

To make sure you’re providing your subscribers with the ability to opt-out of your text program, Klaviyo’s default setting automatically adds opt-out language or an opt-out link (depending on your country) to every text you send.


Read the manual:
If you request a Canadian short code, it’s a compliance requirement to recognize French keywords. If you have an active sending number in Canada, Klaviyo by default, will recognize and respond to French keywords for subscribe, unsubscribe, resubscribe, help, info, and stop.


text message showing us opt out language for marketing
U.S. example of opt-out language added to a message.
sms message with canadian opt-out language
Canadian example of opt-out language and required info link added to a message.
phone with french keyword response
Example of French keywords for SMS.

Only text customers who want to chat with you

Two-way SMS gives you the ability to have real-time conversations with your customers just like you have with your friends and family.

You can answer their questions and support them as they’re making a purchase, all while building a genuine human connection.

But those connections won’t happen if you’re trying to communicate with customers who haven’t signed up to receive your text messages.

To use SMS Conversations, your audience must be subscribed to your SMS list, not just your email list—Klaviyo won’t allow you to use the tool otherwise. That way, you can’t accidentally violate the laws governing SMS two-way chat.

two-way conversation on sms

You gain the ability to see incoming texts from subscribers and instantly respond to them with Klaviyo SMS Conversations. Plus, you can see each subscribers’ profile so you have the relevant information you need to respond in a meaningful way—whether that’s proactively asking a customer if they have questions about the items in their cart or sending a thoughtful text message on their birthday or first purchase anniversary


Not yet ready for a test drive:
SMS Conversations is a feature that’s not currently available in the UK and Australia.


Not only should your SMS platform come with bells and whistles to help you stay legally compliant, but it also should include features to ensure your messages get into your subscribers’ inboxes.

Read on to learn how Klaviyo can effectively deliver your messages.

Need help deciding which SMS provider is right for you?

Chapter 3: SMS deliverability

The main reason you buy a car is to have a vehicle that can take you places. Safety is paramount, but a safe car isn’t all that useful if it can’t actually get you anywhere. 

Similarly, the main reason to choose an SMS marketing platform is to send text messages to your audience. The hope is that through your messages, they’ll engage with you on a channel that’s part of their daily lives and eventually make a purchase. 

An SMS marketing platform that helps you stay compliant is fantastic, but without the ability to deliver, your text messages won’t go anywhere and you’ll miss out on an impactful way to engage your audience. 

Imagine you designed the most perfect, personalized text message of your entire career, but then your subscribers never saw it. All your work would be for nothing.

Enter, SMS deliverability:

  • Deliverability is the ability to land your text messages into your subscribers’ message app.
  • In text message marketing, you’re billed for how many messages you send, not how many of your messages are delivered.


Deliverability is a topic that’s often difficult to understand, which is why it’s important to partner with a platform that provides transparent reporting on how many of your text messages are sent, delivered, and clicked.

how klaviyo text message tool explains why an SMS message wasn't delivered

Not only will Klaviyo share the deliverability rate for each text message you send, but you’ll also see why individual messages weren’t delivered. Klaviyo removes the guesswork for you, saving you valuable time and resources, so you can understand exactly what changes you may need to make to future messages.


Quick tip:
The CTIA prohibits text messages that contain words related to sex, hate, alcohol, tobacco, and firearms (SHAFT). Even if your message isn’t related to SHAFT industries, using words that are similar can keep your texts from being delivered. That’s why it’s best to avoid keywords that increase the likelihood of triggering SMS spam filters.


Plus, once you see which of your messages are delivered and clicked, with your email and SMS together in Klaviyo, you can map out different customer journeys and better attribute customers’ touchpoints to the correct channel.


Deliverability you can count on

What’s the first step in getting your text messages to where they need to go?

Having a phone number to send your messages from.

Flexible options for SMS phone numbers

As you decide what phone number best suits your text messaging needs, check out the available options you’ll find in Klaviyo:

  • Toll-free numbers 
    These numbers begin with a three digit code. They’re free for all Klaviyo customers and you can set them up immediately. Toll-free numbers in Klaviyo can increase their throughput from three to 25 messages per second.Toll-free numbers are available in the US and Canada. 
  • Dedicated short code 
    Short codes have fewer digits than a telephone number and they’re more costly to set-up than toll-free numbers. Because you lease a short code from the U.S. Short Code Administration, you often wait months to receive one. But, you can increase the throughput on short codes exponentially to deliver timely messages to your customer lists no matter their size. Short codes are a good option if you’re planning to send text messages to over 100,000 people per month. Since these numbers are specifically registered to you, carriers trust them more and you can see slightly higher deliverability rates than with other numbers.Short codes are available in the U.S. and Canada, but you can’t use the same short code in both countries. If you’d like to use a short code to communicate with your customers in Canada, you’ll have to lease a separate Canadian short code.  
  • Alphanumeric sender ID 
    This allows you to set your brand’s name as the sender ID or number when you send one-way text messages. This option is only available in the UK and Australia and you get it for free when you partner with Klaviyo.

Just as the type of car you buy depends on your personal needs or lifestyle—a speedy two-seater versus a minivan that seats your entire family—your business needs may differ from those of, say, an enterprise company. 

For example, maybe you’re not ready to commit to the cost of a dedicated short code or you want to get started with text message marketing quickly (short codes take 8-12 weeks to lease). In that case, toll-free phone numbers could be your best option.

You’ll receive a complimentary toll-free number when you sign up for Klaviyo SMS, as well as a complimentary alphanumeric sender ID if you want to send texts to customers outside of the U.S. and Canada. Toll-free numbers have a high deliverability rate, so carrier networks won’t penalize you for choosing this option over a dedicated short code. But you’ll have the choice of upgrading to a short code, if it makes sense for your business needs.

klaviyo dashboard notification that you have a toll free number

Did you know?
Shared short codes can put your deliverability at risk. If you share a short code with a brand that isn’t sending their messages compliantly, you and any other brands using that short code could be in jeopardy. Mobile carriers have recently banned the use of these numbers. Klaviyo has never supported shared short codes.


Speaking of throughput, your subscriber list isn’t a static list. It’ll fluctuate as your SMS list grows, and you’ll likely benefit from an SMS platform that can adapt to the demands of your business. 

Say your list size grew exponentially and you purchased a larger SMS plan, but your new subscribers experienced a delay in receiving your text messages because your SMS platform couldn’t adjust its throughput quickly enough. This could feel clunky for your new subscribers and may make them question why they signed up for your messages in the first place. 

That’s why Klaviyo automatically adjusts your throughput or the number of text messages you can send per second based on your list size—so you can continue to seamlessly send timely messages to your audience as your list grows without a delay.

A phone number that’s verified for you

Would you purchase a new car without registering the car in your name? Probably not. 

A verified phone number is like your car’s registration. It improves your deliverability because aggregators—or the companies that act as an intermediary between your text message marketing platform and carrier networks—then know what unique phone number is associated with your brand and will prevent it from getting caught in a spam filter.

But it can be a tedious process to verify your toll-free SMS number on your own and with everything else you have to work on throughout the day, it could potentially take a backseat to your other tasks. 

That’s why Klaviyo will verify your toll-free number for you and you’ll receive a notification as soon as it’s been verified.


Head’s up:
Regulated industries such as firearms and marijuana-related products can’t register their phone number for legal reasons and regulations put in place by mobile carriers. Also, when carriers decide whether to prohibit or allow messages related to a product or an industry, they consider the laws and regulations at the federal level, not at the state level.


Text messaging notification you receive when your number has been verified

Access to the most advanced SMS services available

Compared to email, SMS is a fairly new marketing channel. As you test drive SMS, having the ability to use text messages in a way that’s tailored to you means you can have better control over the customer experience you’re trying to create. 

Because Klaviyo is able to lean on the combined power of its long-standing email and SMS business partnerships (like Twilio), you have access to one of the best SMS services the industry provides, which means you won’t lose sleep over whether your subscribers are receiving your messages.

Like a car that will get you from one place to another, Klaviyo will get your messages into your subscribers’ device—signed, sealed, delivered.

Chapter 4: Compliance and deliverability aren’t roadblocks

SMS compliance and deliverability shouldn’t get in the way of your ability to build relationships with your customers. When you choose an SMS provider like Klaviyo, you can feel confident that compliance and deliverability features are built natively into the platform—so you can worry less and focus more on creating delightful moments for your customers.

The most dazzling customer experiences are ones that combine the power of SMS and email marketing to create a cohesive journey across every point of interaction with your brand. With your marketer’s manual in hand, you’re prepared to take SMS marketing for a spin and explore how you can bring your email marketing along for the ride.

Ready to build better customer relationships with email and SMS marketing?

About Klaviyo

Klaviyo is a world-leading marketing automation platform dedicated to accelerating revenue and customer connection for online businesses. Klaviyo makes it easy to store, access, analyze and use transactional and behavioral data to power highly-targeted customer and prospect communications. The company’s hybrid customer-data and marketing-platform model allows companies to grow by fostering direct relationships with customers, without giving up their valuable data to popular big-tech ad platforms. Over 265,000 innovative companies like Unilever, Custom Ink, Living Proof and Huckberry sell more with Klaviyo. Learn more at