Both email and SMS marketing have strong ROI numbers. Both are owned channels where you have direct access to your audience without paying for reach. And both are frequently pitted against each other by software vendors trying to sell you on one or the other. The honest answer for most Shopify brands is that they are not competitors — they are complements. But understanding where each channel performs best helps you use both more effectively.
The Core Difference
Email is a content channel. SMS is an urgency channel. That single distinction explains most of the differences in how they perform and where they belong in your marketing stack.
Email can carry long-form storytelling, editorial design, product education, multiple images, and complex offers. Subscribers expect it to take a minute to read. SMS must be short, direct, and immediately actionable — or it will be ignored or cause an unsubscribe.
Open Rates
SMS open rates are often cited at 98%, compared to 20–40% for email. This is technically accurate and also somewhat misleading. SMS is opened because a notification appears on the phone's lock screen — most people glance at it regardless of sender. Email is opened by deliberate choice. A 25% email open rate represents genuine intent; a 98% SMS open rate includes many people who glanced and immediately deleted.
What actually matters is clicks and conversions, not opens. Email and SMS perform similarly on conversion rates when sent to the right audience at the right moment.
Where Email Wins
- Product education and storytelling. Explaining a product, sharing a founder story, or building brand affinity requires space. Email gives you that space.
- Visual presentation. Photography, brand design, layout — email is where your visual identity can shine. SMS is text-only.
- Campaign frequency without alienating subscribers. Subscribers accept more email frequency than SMS. 3–5 emails per week is normal for active DTC brands. 3–5 SMS per week would cause mass unsubscribes.
- Cost at scale. Email costs are typically fixed or volume-based at a fraction of a cent per send. SMS costs $0.01–$0.05 per message, which adds up quickly on large lists.
- Automation depth. Welcome series, post-purchase flows, win-back sequences — email automation is more sophisticated and better-supported across ESPs than SMS automation.
Where SMS Wins
- Flash sales and time-sensitive offers. A 4-hour sale or a last-chance restock notification works better via SMS because it reaches people immediately with high visibility.
- Transactional updates. Shipping notifications, order confirmations, and delivery alerts feel natural in SMS and get read immediately.
- Back-in-stock alerts. Customers who requested a restock notification want to know the moment it is available — SMS delivers that.
- Two-way conversations. Some SMS platforms enable real back-and-forth messaging, which email does not support natively.
Costs Compared
For a list of 10,000 subscribers sending weekly:
- Email: $50–$150/month on most ESPs (Klaviyo, Omnisend) at this list size. Effective cost of about $0.001–$0.003 per send.
- SMS: $0.01–$0.05 per message. 10,000 subscribers × 4 sends per month = $400–$2,000/month.
SMS can deliver strong ROI at that cost — but it requires tighter targeting and more selective sending to justify the spend. Sending every subscriber every SMS message is rarely the right approach.
The Combined Approach
The brands generating the most from owned channels use both. The typical structure: email handles the content programme (regular campaigns, flows, brand storytelling), and SMS handles high-urgency moments (flash sales, restock alerts, abandoned cart final nudge). The two channels reinforce rather than compete — a subscriber who receives your regular email content and your SMS sale alerts is better reached than one who only gets one or the other.
If you are choosing where to start, start with email. Build the list, establish the automation flows, and develop the content programme. Add SMS once email is generating consistent revenue and you have a specific use case — a flash sale programme, restock alerts, or an abandoned cart sequence — where the immediacy of SMS adds real value.
For building that email foundation, Shopify Email Marketing for Beginners covers the seven campaigns every store needs to have running.