Email vs. SMS: The Role of Each Channel in a High-Performing Retention Strategy
As brands invest more in owned marketing channels, one question comes up repeatedly: How should email and SMS actually work together?
Too often, the default approach is simple but ineffective: Send everything everywhere.
The reality is that the most effective retention programs treat each channel differently. Email and SMS serve distinct roles, and when those roles are respected, both channels perform better.
Understanding how each channel contributes to retention is what separates programs that simply send messages from those that consistently generate revenue. At 624, we see email as the foundation, and SMS as the accelerator — working together across the customer lifecycle. From automated touch points like welcome series, post-purchase follow-ups, and browse or cart abandonment flows, to campaign moments that drive urgency, both channels play a critical role in delivering timely, behavior-driven messaging that keeps customers engaged and coming back.
The Foundation of Retention: Email
Email remains the backbone of most retention programs for a reason: it allows brands to communicate with depth.
Unlike SMS, email gives marketers the space to tell a story, educate customers, and present multiple products or ideas at once. It’s the channel best suited for building long-term brand affinity while also driving routine revenue.
Email excels at product storytelling, educational content, merchandising, brand-building campaigns and routine promotional cadence.
In short, if a message needs depth or explanation, email is your best bet.
The Accelerator: SMS
SMS, or short message service, plays a very different role. While email builds the foundation, SMS amplifies high-intent moments. Text messages are immediate, direct, and highly visible. Because of that, SMS works best when the copy is clear, urgent and actionable.
Most importantly, SMS should not simply replicate email campaigns. Instead, it should selectively support moments where speed and visibility matter most. For example, time-sensitive, expiring offers like flash sales or last-chance reminders are the perfect candidates for an SMS campaign. When a customer has a short window to act, the immediacy of a text message helps to drive a faster response.
SMS can also be highly effective when used as part of automated lifecycle messaging triggered by customer behavior. From browse and cart abandonment to checkout reminders, these real-time touchpoints bring customers back to complete actions they’ve already started. It’s also an impactful way to nudge customers to restock on their favorite products or explore new collections, meeting them at the right moment and making it easy to take the next step.
Shipping notifications, VIP-only offers, delivery confirmations, and order updates are another natural fit for SMS, since customers typically want these updates in real time.
Why Strategic Brands Don’t Send Everything, Everywhere
A common mistake brands make is assuming that more messages across more channels automatically leads to more revenue. In practice, the opposite often happens. SMS is an interruptive channel, unlike email, which customers can read on their own time, text messages demand immediate attention.
That’s why it’s not just about choosing the right channel, but also the right audience. Not every message should go to your entire list. Effective programs rely on thoughtful segmentation — using behavior, purchase history, and engagement to ensure each message is relevant, timely, and more likely to convert.
Because of that, overusing SMS has consequences, including an increase in opt-out rates, decrease in engagement, and conversion per send dropping. When brands dramatically increase SMS frequency, performance usually falls over time. This is why we encourage clients to treat SMS like premium real estate. Every send should feel intentional and valuable to the customer.
One of the most overlooked principles of retention marketing is cadence discipline. It’s not just a compliance tactic, it really does impact performance.
When Should We Use SMS?
When deciding whether a message belongs in SMS, two simple questions can help guide the decision:
1. Is this time-sensitive?
If the message loses value quickly — like a flash sale or expiring offer — SMS may be the right channel.
2. Is the message short and actionable?
SMS works best when customers can understand the message instantly and take action with a single click.
If the message requires explanation, storytelling, or multiple product options, email is likely the channel we’d recommend.
3. Is this message relevant to a specific customer segment?
Strong SMS programs rely not just on channel selection, but also segmentation and relevance.
What is the Future of Mobile Messaging?
As mobile messaging continues to evolve, we’ll likely see richer formats emerge. Technologies like RCS (Rich Communication Services) are already expanding what messaging can support — including images, carousels, and interactive elements.
But even as messaging becomes more visual and dynamic, one principle will remain true: No matter how advanced messaging technology becomes, brands that respect cadence, maintain relevance, and use each channel intentionally will continue to outperform those that simply send more messages.
When each channel is used for what it does best, brands can create a communication strategy that drives long term growth and loyalty. Is your brand ready to take the next step and build an email and SMS strategy that actually works? Let’s chat.