SMS is one of the most powerful channels available to e-commerce brands, and it is also one of the easiest to get wrong. So many brands tend to think of SMS from the lens of their own personal experience. If you’re someone who doesn’t like SMS, then maybe you are hesitant to implement an SMS program because you find it to be invasive. However, a well-timed, relevant text message from a brand you like can feel like a genuine service. A poorly timed, generic blast can feel like an invasion. The difference comes down to how you build your SMS program, not whether or not you have one.
Klaviyo’s native SMS product is built directly into the platform, which means your email and SMS programs share the same data, the same audience segments, and the same flow builder. That integration is what makes Klaviyo SMS particularly powerful for e-commerce brands that are already using Klaviyo for email. You are not adding a new tool. You are adding a new channel to a system you already have.
Here is how to do it right.
Why SMS Deserves a Seat in Your Marketing Mix
The performance data on SMS is hard to argue with. Text messages have an open rate of 98 percent compared to an average of roughly 35 to 45 percent for email. The average time to open an SMS is three minutes. Click-through rates on SMS messages are consistently higher than email for time-sensitive promotions.
These numbers exist because of how differently people relate to their text message inbox versus their email inbox. Email has become a managed channel for most people, something they check on their own schedule and filter actively. Text messages feel more immediate and personal, which is exactly why the stakes are higher when you get them wrong.
The opportunity is real. The responsibility to use it well is equally real.
How to Collect SMS Opt-Ins the Right Way
Unlike email, where the legal standards for consent vary, SMS marketing in the United States is governed by the Telephone Consumer Protection Act (TCPA) and requires explicit written consent before you can send marketing messages to anyone. This is not a technicality you can work around. It is a legal requirement, and violations can result in significant fines.
Explicit consent means the subscriber has clearly agreed to receive marketing text messages from your brand, typically through a checkbox, a keyword opt-in, or a standalone sign-up form specifically for SMS. Providing an email address does not constitute SMS consent. Placing an order does not constitute SMS consent.
In Klaviyo, you can collect SMS consent through your sign-up forms by adding a phone number field alongside your email capture, or through a standalone SMS opt-in form with a compliant consent checkbox and the required legal language about message frequency and data rates.
Do not try to grow your SMS list through shortcuts. A smaller SMS list of genuinely opted-in subscribers will outperform a large one of people who did not explicitly sign up, and it will not expose your business to legal risk.
Before you launch any SMS program, there is one step that often gets overlooked: your website’s Privacy Policy and Terms of Use pages need to be updated to reflect your SMS marketing practices. Specifically, your Privacy Policy should disclose that you collect phone numbers, how that data is used, and that subscribers may receive marketing text messages.
Your Terms of Use should outline the terms of your SMS program, including message frequency, data rates, and how subscribers can opt out. Many SMS opt-in forms are required to link directly to these pages as part of the consent language. If those pages do not address SMS, your consent collection is incomplete from a compliance standpoint, regardless of how well your sign-up form is written.
Starting with the Right SMS Flows
The best way to start with Klaviyo SMS is to layer it into flows you are already running rather than building an entirely new SMS-only program from scratch.
Abandoned Cart is the highest-impact starting point for most brands. Adding an SMS message to your abandoned cart flow, sent to subscribers who are opted in for both channels, gives you a second touchpoint with cart abandoners who may not have opened your email. A simple text that says “Hey, you left something in your cart. Here is a quick link to grab it” can recover sales that the email alone missed.
Welcome Flows are another natural entry point. Adding an SMS to your welcome series, perhaps after the first email, reinforces the opt-in and starts the channel relationship on a positive note with something of value.
Winback campaigns can also benefit from a cross-channel push. A lapsed customer who has stopped opening your emails might still respond to a direct text, particularly if it includes a strong offer and feels personal.
The Rules of Good SMS Copy
Text messages are not emails. They have a strict character limit (typically 160 characters for a standard SMS), no images in the basic format, and they arrive in the most personal communication channel most of your customers own. The copy standards for SMS are therefore different from email.
Be direct and get to the point immediately. There is no room for a lengthy setup. Your first sentence needs to communicate who you are and what you are offering.
Always identify yourself. Subscribers should know within the first few words that the message is from your brand. Something like “Hey [first name], it is [Brand Name]” at the start of the message removes any confusion about who is texting them.
Make the action clear and easy. Every SMS you send should have one job and one link. A text that asks the subscriber to do multiple things or includes multiple links creates confusion and reduces conversion.
Include the required opt-out language. FCC regulations require that your subscribers have the ability to opt out of SMS at any time, typically by replying STOP. Klaviyo handles this automatically, but you should be aware of it and make sure your messages include clear opt-out information where required.
How Often to Send SMS
Less is more with SMS, at least until you have established a strong rapport with your SMS subscribers. Sending too frequently is the fastest way to generate opt-outs from people who liked you enough to sign up but felt overwhelmed by the volume.
For most e-commerce brands, four to six SMS messages per month is a healthy ceiling for standalone campaigns. This covers roughly one send per week, which is enough to stay present without wearing out your welcome.
For flow-based SMS, frequency is managed by the trigger and the logic you build into the flow. A subscriber who abandons a cart and receives one SMS as part of the flow is a different situation from someone on your broadcast SMS list receiving a promotional blast.
Pay attention to your opt-out rate on every SMS send. A consistent opt-out rate above two percent is a signal that you are either sending too frequently, your content is not relevant enough, or your audience did not fully understand what they were signing up for.
Integrating SMS and Email for Cross-Channel Flows
The real power of Klaviyo SMS comes from using it in coordination with email rather than as a standalone channel. Cross-channel flows let you reach subscribers on the channel most likely to get a response, at the right moment, with the right message.
A common and effective cross-channel pattern is email first, then SMS. In an Abandoned Cart flow, for example, you might send an email at 45 minutes and then an SMS four to six hours later to subscribers who received the email but did not open it. The SMS then reaches people the email missed, without doubling up on people who already engaged with the email.
You can build this logic directly in Klaviyo using conditional splits based on email open behavior. If the subscriber opened the email, skip the SMS. If they did not, send the text. That kind of smart channel orchestration is what separates an annoying multi-channel blast from a thoughtful multi-channel experience.
SMS done well is not about sending more messages. It is about sending the right message through the right channel at the right moment and meeting your customers and potential customers where they’re at. When you get that balance right, it becomes one of the most effective revenue drivers in your marketing mix.
If you want help building out your Klaviyo SMS program or integrating SMS into your existing email program, we are happy to walk through it with you.
Continue reading: The essential Klaviyo integrations every store should enable and Abandoned cart email strategy: Timing, copy, and offers that work.