3 tips to grow a healthy SMS subscriber list

In the past, email likely played a big part in your CX strategy — and the initial results showed promise. But as more and more brands caught wind of the benefits of email marketing, customer mailboxes became crowded. 

Now, email is more of an annoyance than a value add. Instead of increasing engagement, they’re turning customers off. If you’re using email as the main source of interaction with your customers — for updates, promotions, delivery tracking, and so on —  it’s safe to assume most of your communications are being sent straight to the trash.

Convenience is everything in a digital world. Brands need to start thinking about faster and more efficient ways to reach and interact with customers. How, you ask? Enter SMS.

Proactive SMS can be a powerful tool to add to your Automated Brand Interaction (ABI) arsenal. It allows you to meet customers where they are with timely, proactive communications that break through the clutter, and are more likely to encourage action.

SMS open rates are as high as 98% while email only reaches as high as 20%

But first you will need to grow your list of SMS subscribers. Keep in mind that in most regions it’s illegal to send someone an unsolicited SMS — you need to follow the necessary steps to obtain proper consent from your customers*, or you run the risk of losing their loyalty for life. 

1. Understand the laws in your customers' regions

We truly can’t emphasize this enough: in order to send customers SMS communications, you need their consent. In some cases, express consent is required — in other cases, implied consent may be acceptable. The laws differ by region, depending on where your customers are located.


The Telephone Consumer Protection Act (TCPA) restricts telemarketing communications via voice calls, SMS texts, and fax. There’s also the industry self-regulatory requirements administered by the Cellular Telecommunications Industry Association (CTIA), which regulates the use of SMS short codes. You will need to be compliant with both, as well as with any state-specific laws.

Controlling the Assault of Non-Solicited Pornography and Marketing Act of 2003 (CAN-SPAM) makes it illegal to send any unwanted “commercial” electronic message, including email and SMS. Businesses need to label any promotional message as an advertisement, as well as allow consumers to opt out of future messages.


Canada’s Anti-Spam Legislation (CASL) — the federal law dealing with spam and other electronic threats — protects users from spam and provides them with an avenue to report spam should they need to do so. It requires businesses to obtain consent to send promotional messages and give customers the ability to opt out of messages — as well as keep records of how and when such consent was obtained.

Canadian Common Short Code Guidelines govern the use of short codes for text message promotions and is administered by Canada’s Wireless Telecommunications Association. 


The General Data Protection Regulation (GDPR)  is largely regarded as the strictest data protection and privacy law in the world. Even if your organization is not located in the European Union (EU) or the European Economic Area (EEA), if you target or collect data related to people who are, you need to abide by the laws outlined in GDPR This includes getting prior consent before collecting an individual’s email address or phone number.

The EU e-Privacy Directive (soon to be replaced by a new e-Privacy Regulation) regulates cookies, email marketing, and other aspects of data privacy in the EEA and also prohibits the sending of unsolicited text messages.

While it’s important to take time to understand the nuances of these different laws, they are consistent in that they generally require brands to obtain consent from prospects and customers prior to sending them SMS communications.

2. Identify tactics to collect customer consent

What is express consent?

Express consent occurs when a customer or prospect explicitly opts in to receive SMS communications from your brand. You’ve likely come across this when you’re buying something online. This might show up as a sign up unit on a brand’s homepage or during the checkout process, and it usually involves checking a checkbox to opt-in to receive future SMS marketing messages. And, if you’re lucky, you might even get a discount on future purchases, too.

Unlike implied consent (also called inferred or implicit), someone simply providing you with their phone number is not sufficient proof of consent. They need to directly tell you they want to receive SMS communications from your brand, in addition to any other communications.

Best practices for obtaining express consent

The best way to obtain express consent is by including this as an optional opt-in checkbox on a form —  unmarked by default. 

The checkbox should be specific to opting into SMS communications, with a direct description that makes it crystal clear that subscribers are signing up to receive automated, recurring promotional SMS communications, and how often they should expect to receive these communications. You’ll need to provide a link to your terms and conditions and privacy policy here as well.

Once someone has opted in to receive SMS communications, provide confirmation over SMS including your brand’s identity, message frequency, the fact that message and data rates may apply, and opt-out instructions. If you are using short codes, your messages will also need to comply with the applicable short code guidelines.

While these guidelines may seem limiting, they help to ensure that you are only sending SMS communications to customers that want to receive them. This will result in a higher quality list of subscribers who are more likely to read and engage with your SMS communications.

Effective ways to grow your subscriber list

Assess customer data and insights to determine when a customer is most likely to provide consent, and set up your approach to ensure they’re receiving this notification at the right moments in their journey. Essentially, you’ll want to hit them with this when they’re already engaged and motivated to interact with your brand. Some examples of key moments to collect consent are:   

  • During sign up or when a purchase is being made. Customers who are signing up for a product, service, or making a purchase are clearly interested in your brand and are likely excited to do business with you — this is the perfect time to collect consent. It’s also smart practice to ensure the customer has options: do they simply want transactional or delivery notifications, or would they like to receive ongoing marketing communications from your brand?
  • During proactive web interactions. With a brand interaction platform that integrates and centralizes all your customer data sources, you can get creative with how you target website visitors. Decide who to show the campaign to and when, based on traffic source or search keyword, or target visitors who have recently purchased. If your ABI strategy includes live agent handoff, you can ask customers to provide their consent prior to the transition to a live agent.

proactive sms campaigns dashboard 

  • In collaboration with incentives that encourage sign ups. For ecommerce brands, discount codes provide that extra nudge a customer may need to get them over the finish line. You can also try running a limited time contest with a chance to win a gift card from your brand. If you’re a B2B company, consider using SMS opt in to gate free content resources, whether that be a study, a whitepaper, a calculator, or a pre-recorded webinar.
  • In existing marketing emails. Gain SMS opt-ins from people that you already know like to hear from you. Promote your SMS communications by providing a link to the form sign up or with a phone number they can text to subscribe.

3. Document SMS consent

Keeping a healthy SMS subscriber list isn’t a one-and-done effort. You will need to keep a record of each customer’s consent, and many CRMs offer easy-to-implement solutions to document and track this. This can include a timestamp of when the consent was checked during sign-up.

Salesforce Sales Cloud and Salesforce Service Cloud have a MessagingEndUser object that can be used to document and track customer consent across various channels. And with a brand interaction platform, you can integrate the data from various locations into one single source of truth. This enables you to keep the consent on file — you’ll need to do this anyway, for at least the statute of limitations under the applicable SMS laws in your customers’ regions.

The benefits of building an SMS subscriber list

Investing in building your SMS subscriber list may seem daunting at first, but SMS is an essential tool in every marketer’s tech stack:

  • Reach targeted users and encourage action, with timely conversational experiences that drive conversion. Proactively update customers with the information and offers they care about.
  • Connect with customers in the channel of their choice. With brand interactions increasingly taking place on mobile, it’s more important than ever to meet customers where they are — and provide a consistent, connected brand experience across each customer touchpoint.
  • Proactively continue the conversation. No matter where the conversation was initiated, proactively pick it up via SMS to increase engagement, deliver a hyper-personalized experience, and drive revenue.

*The content provided in this blog post is for informational purposes only and does not constitute legal advice. Ada recommends that you consult with your legal counsel to make sure that you comply with all applicable laws in your region and the regions of your customers. Ada disclaims all liability for any content contained herein or any damages arising from your use of the content.

Rob Reardon
Rob Reardon

Rob Reardon is a Senior Product Manager at Ada who loves to innovate solutions to customer problems. Prior to working in technology, Rob was a B2C marketer, a park ranger, and a drama camp counselor.

More info about Rob Reardon: LinkedIn

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