14 tips for growing your SMS list and getting more opt-ins—without breaking compliance laws

Profile photo of author Jax Connelly
Jax Connelly
15min read
SMS marketing
May 8, 2024
In lavender capital letters on a salmon background, copy on the left side of the image reads, "GROW YOUR SMS LIST." In smaller copy underneath that, text reads, "14 tips for getting more opt-ins without breaking compliance laws." On the right side of the image is a sign-up form on someone's phone, positioned next to an illustration of the SMS dashboard in Klaviyo.

Healthy SMS list growth is one of the biggest factors in generating revenue from SMS marketing.

But it’s easy to accidentally go about it the wrong way.

SMS is a marketing channel that requires explicit consent—and the potential consequences for brands that don’t comply with SMS compliance laws range from steep fines to an expensive lawsuit to deliverability issues to list deterioration.

According to Melissa Matusky, manager and implementation consultant at Klaviyo, consumers will unsubscribe from an SMS list far faster than from an email list. “They can ignore a junk email inbox, but they cannot ignore messages that go to their direct phone,” she points out.

Being really smart about compliance is what drives SMS list growth, and continually building that SMS list is what drives strong ROI.
Melissa Matusky
Manager and implementation consultant, Klaviyo

If your SMS unsubscribes spike and your list growth remains stagnant, “you’re going to see diminishing returns, because now more people are opted out than opted in,” Matusky explains. “That means the value’s going to go down in that channel.”

“SMS compliance is a proactive game,” Matusky adds. “Being really smart about compliance is what drives SMS list growth, and continually building that SMS list is what drives strong ROI.”

Here are 14 tips for getting more SMS subscribers—without breaking compliance laws around SMS marketing.

1. Hammer down your policy language

Setting up your SMS disclosure language can be “a little bit scary and daunting,” says Mason Wheeler, former customer education specialist at Klaviyo. “But it shouldn’t be a barrier to getting started. You just need to be intentional about it.”

Your mobile terms of service and your privacy policy both need to be linked from your SMS sign-up form—a process automated by SMS marketing platforms like Klaviyo, Matusky says.

Jess Schanzer, lead product marketing manager at Klaviyo, adds that two recent Klaviyo product updates “make it even easier to set that language up compliantly, whether you’re brand-new to Klaviyo SMS or you’ve been using us for a while”.

For new users

“We’ve always had compliance built into our platform, but now, as you’re going through the onboarding workflow, you’re prompted step by step through everything that has to do with disclosure language,” Schanzer says. “That way, every single sign-up form you create moving forward is going to include that language so you never have to do it again.”

For veteran users

“If you want to make updates to your disclosure language, you can now do that from directly within sign-up forms and within your SMS account settings as well,” Schanzer says.

2. Launch SMS sign-up forms—and target the right people

Whether they’re embedded, pop-ups, or fly-outs, on-site sign-up forms are the “No. 1 most effective SMS list growth tool,” Schanzer says.

“The pop-up is such a major portion of your SMS list growth that you really have to nail that piece of it,” says Jacob Sappington, head of email at ecommerce growth marketing agency Homestead Studio, who recommends using multi-step forms that collect email addresses first, then ask for SMS on the second screen.

Gif shows an example of a multi-step sign-up form, where the first page asks the visitor for their email address, the second page asks them for their phone number, and the third page thanks them for signing up.
Image source: Zettler Digital

Schanzer adds that because Klaviyo cookies and tracks website visitors who are already on your existing email list, you can also serve a unique pop-up form to existing email subscribers, inviting them to join your SMS list as well.

Then, they’ll be funneled into a unique list in Klaviyo for subscribers who are opted in to both email and SMS—and all of it happens automatically on the back end, with no manual input from you.

3. Send a “sign up for SMS” email campaign

On that note: Because your email subscribers already care about your brand, they’re probably more likely than random website visitors to become engaged SMS subscribers.

“These are people who are already in our CRM, who are already in our funnel,” Sappington points out. “They’re willing to be a little bit deeper ingrained in your business because you have something to offer that they like.”

Consider creating an invitational email campaign segmented to email-only subscribers, encouraging them to opt in to texts.

Here’s a great example from kids’ apparel brand Cheeky Chickadee, a client of global customer journey agency Andzen. “To create hype around new season launches, we’ll send a teaser email alerting customers that a new collection is dropping soon—but we won’t always reveal the details,” explains Natasha Hanley, copywriter at Andzen.

“To play into the hype, we let email subscribers know that if they opt in to SMS, they’ll receive early access to shop the drop,” Hanley explains. “This creates a sense of exclusivity and gives customers a great reason to opt in to SMS.”

Image shows an email campaign from kids’ apparel brand Cheeky Chickadee, a client of Andzen. The email uses an autumn color palette with a dark sepia background and illustrations of leaves in the four corners. In white font, the email reads, “Buzz buzz, it’s us! Want to be alerted the moment the collection launches? If you’re part of the Cheeky flock, we’ll text you with your password for early access.” An orange CTA button in the middle of the email reads, “click here.”
Image source: Andzen

4. Promote your SMS program on social

If your SMS program has been around for a while, “pop-ups aren’t really moving the needle in terms of sign-ups,” points out Blair Peterson, VP of strategy at ethical jewelry brand Dana Rebecca Designs. “You have to get a little more creative.”

When Dana Rebecca Designs first launched their SMS program, they offered giveaways and other incentives for new SMS subscribers, like selecting someone who just signed up for SMS and sending them a free jewelry cleaner kit—no purchase required.

Cross-channel promotion helps with those kinds of giveaways, Peterson observes: “We really leaned into talking about that on social. So at the beginning of the month, we’d post about how we were going to pick somebody this month who signs up, and then at the end of the month we’d announce the winner.”

In Klaviyo, you can accomplish this kind of thing with SMS subscribe links, or even allow people to sign up for texts through Instagram stories.

When someone makes a purchase on your website, they have to input their contact information as part of the check-out process. That’s a great time to ask if they want a text receipt, and give them the option to check a box if they also want to sign up for SMS marketing.

It’s all about “making it easy for the subscriber, “so they don’t have to give you their information all over again,” says Rob Hand, lead product marketing manager at Klaviyo.

Klaviyo also offers order updates via SMS. Available for Shopify customers, this feature allows you to collect and store transactional consent separately from marketing consent—which can be a great way to introduce SMS to a new customer. Just remember that transactional SMS is not the same as marketing consent and is only valid for one purchase at a time.

Learn how to use Klaviyo to:

6. Think outside the box with QR codes

This is one of Matusky’s favorite creative use cases for SMS list growth: QR codes on shipping boxes, product instructions, or product labels, where “you’re asking people to opt in to get help using their product,” she explains.

7. Get permission—and confirm it, twice

No matter how you’re getting people to sign up for your SMS list, an important best practice is using double opt-in to confirm that you have their explicit consent to receive SMS marketing.

In this practice, after a subscriber signs up for SMS marketing, they must also confirm their sign-up by replying something like “YES” when they receive the first text from your brand.

“A lot of marketers have concerns about slow list growth because they’re making people take that extra step to reply YES, but ultimately it’s better to grow your list with high-quality leads and people you know will respond,” Matusky explains. “If you know somebody isn’t willing to respond to a text message from you with a YES, they’re probably not very invested in the channel.”

If you know somebody isn’t willing to respond to a text message from you with a YES, they’re probably not very invested in the channel.
Melissa Matusky
Manager and implementation consultant, Klaviyo

Klaviyo makes it easy to manage SMS subscriber consent, Hand says: “We only accept explicit consent, meaning every subscriber has actively checked a box agreeing to give you their phone number for X reason. Everything thereafter compliance-wise, outside of policy language, is automated in Klaviyo.”

Coming soon to Klaviyo is another useful feature for simplifying the process of collecting SMS consent: SMS Smart Opt-In, which simplifies the opt-in process by sending a one-time passcode that allows visitors to quickly join a list via autofill.

8. Make it easy to opt out

Even if you’re doing everything right, some of your SMS subscribers may eventually decide they no longer want to receive texts from your brand. It’s therefore important to give your SMS subscribers an easy way to opt out—in every text you send.

It may seem counterintuitive, but you don’t want to waste money sending texts to someone who doesn’t want to hear from you. And if you text someone who wants to opt out but can’t, they may report you.

Matusky says this step is as simple as including either an unsubscribe link or a keyword response opt-out option, such as “STOP.” (Marketing platforms like Klaviyo, which have compliance features built in, automatically handle this for users.)

9. Set expectations from the get-go

Matusky recommends that you “know your intention” when you launch an SMS marketing program. Then, be transparent about it when asking people to opt in.

“Know what types of messages you’re going to be sending so you can articulate that at the point of sign-up,” she suggests. “Anything where you’re really clear about what they’re going to receive is going to work really well.”

What are your SMS subscribers opting into? It might be:

  • Transactional SMS, like order and shipping confirmations
  • Conversational or two-way SMS, for customer support and immediate feedback
  • Educational content, like links to new recipes involving your products
  • Marketing messages about new product launches, sales, and more

“Provide some explicit content around what they’re going to receive,” Hand recommends. “If you’re not upfront with subscribers, they’ll get upset, unsubscribe, and complain.”

In addition to being transparent about content, set expectations about frequency as well. A consumer who signs up for SMS marketing and receives 2 messages the first week might get annoyed and unsubscribe—but not if they know you’re only sending 3 per month.

10. Offer something better than a discount

More than any other sign-up strategy, this one’s most important, Sappington says: “There needs to be a strong reason for someone to get on your list. If you’re just saying, ‘Hey, join our list,’ it’s going to fall flat. People don’t sign up unless you give them a reason to.”

Hot tip: A discount doesn’t qualify as a “strong reason.”

“Discounts are honestly the least exciting thing you can do with SMS,” Schanzer says. “It’s so overrated and overdone.”

But even worse than being boring, discounts may actually detract from list growth. Hand refers to it as a “spin to win” SMS strategy—and points out that it’s actually not much of a strategy at all.

Discounts are honestly the least exciting thing you can do with SMS. It’s so overrated and overdone.
Jess Schanzer
Lead product marketing manager, Klaviyo

“When you use something gimmicky to get someone to sign up—‘Hey, give me this information about you and I’ll give you a discount in exchange’—you’re not really setting up a relationship with that person,” he explains. “It’s become this transactional game you’re playing, and that just doesn’t feel good as a consumer.”

“If you’re just going for deals, deals, deals, and you’re not being strategic about what you’re offering when and why, it’s going to feel spammy,” Matusky agrees. “It’s going to cause people to opt out and not interact, and that’s going to lower your ROI.”

Compared to discounts, Schanzer says, “there’s just so much more you can do with SMS—things that aren’t salesy but are rather helpful.”

11. Build SMS as a VIP channel

One “strong reason” to get people to sign up for SMS: Reserve your SMS channel for sharing exclusive content, early access to product drops and sales, and behind-the-scenes sneak peeks.

This is a powerful strategy for maintaining SMS list growth because treating SMS subscribers like loyal insiders makes them proud to build a unique relationship with your brand.

For their client Little Party Dress, the Andzen team segments subscribers into 4 loyalty tiers to reward the brand’s best customers. The loyalty program, Club LPD, was created to replicate the feeling of an exclusive nightclub that doesn’t let you in unless you’re on the guest list.

“We send early-access SMS marketing campaigns for their biggest launches and events, like Black Friday Cyber Monday, and we stagger it by loyalty program tier, so the higher up you are in Club LPD, the earlier access you get,” Hanley explains.

“Customers in the top loyalty tier, the VIP Lounge, are often given access 24 hours before members of the lowest 3 tiers,” she adds.

In pink font on a black background, image lists details of the Little Party Dress VIP club: “Early access for Club LPD members. We’ll send out an email and SMS to let you know when your early access window has opened, with instructions on how to redeem the Black Friday offer before the public!” Next comes a checklist with 3 items: “VIP lounge: 5 p.m. Tuesday 23rd Nov,” “Rooftop bar: 8am Wednesday 24th Nov,” and “Dance floor and guest list: 5pm Wednesday 24th Nov.” At the bottom is a pink CTA that reads, “sign up for early access.”
Image source: Andzen

The higher the loyalty tier, the better the results: The top tier of customers converted at an astounding rate of 20.31%.

12. Use two-way SMS to support and include customers

Remember: SMS doesn’t have to be a one-way communication channel. You can also use SMS conversations to create a dialogue with subscribers and increase engagement.

For starters, integrate help desk apps like Gorgias and Zendesk with your SMS marketing platform to manage all customer communications in one place and power highly targeted campaigns, such as excluding customers with open support tickets from promotional campaigns.

Elliot Scott, founder and CEO of London-based retention agency ElliotDigital, also uses two-way SMS to ask customers to share their honest insights and opinions. How was their last order? What’s their favorite product? What could you be doing better?

That’s an especially smart strategy with repeat purchasers, says Ben Zettler, founder of digital marketing and ecommerce agency Zettler Digital.

“Reach out to your loyal customers, such as people who have bought from you 5x, with a text message saying, ‘Thanks for completing your 5th purchase. We would love to know what’s your favorite thing and what’s your least favorite thing about what we’re doing,’” Zettler advises.

“It’s another avenue to try to engage with users, and it breaks through the noise of email,” Zettler adds. “Plus, customers appreciate gestures like that from the brands that they’re interested in.”

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13. Make texting a game—literally

Scott’s team is currently experimenting with creative ways to make SMS marketing interactive—and fun. That might mean sending out a text message that:

  • Offers a discount to the first 20 subscribers who find a hidden code on a linked custom landing page
  • Promises to select one winner at random out of everyone who solves a word game on a linked custom landing page
  • Offers a prize to the first subscriber to reply correctly to a quiz question about the brand’s history

Not only are people more likely to redeem their coupon codes or free gifts when they’ve done something to earn them—gamifying your owned marketing channels in this way can train subscribers to expect rewards for engaging with your emails and texts, rather than expect discounts before buying.

“It’s just psychology, right? If you work for something, you’re invested. When you’ve earned the reward, you’re more likely to use it—especially if there’s urgency attached as well,” Scott points out. “People want to feel like they’ve earned something, instead of you just throwing money at them like every other brand in the whole world does.”

14. Be patient

Remember: “SMS is a more intrusive channel, so it’s rare to go from 0 to 100K overnight,” says Morgan Mulloy, associate director of email marketing at Avex Designs. “Just like a new plant, your SMS list needs nurturing.”

“The payoff,” Mulloy adds, “will be worth it.”

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Jax Connelly
Jax Connelly
Lead editor
Jax Connelly (they/she), lead editor at Klaviyo, started their career doing SEO at a small digital ad agency and spent most of their twenties managing a financial magazine for a trade association based in Washington, DC. Most recently, she studied and taught writing at Columbia College Chicago during the peak years of the pandemic. Outside of their day job, Jax is an award-winning creative writer who has received honors including 4 Notables in the Best American Essays series, contest awards from publications like Nowhere Magazine and Prairie Schooner, and a residency from the Ragdale Foundation. Jax lives in Chicago a block away from Lake Michigan with her elderly Jack Russell Terrier, Cloo.