WhatsApp vs. SMS vs. email: how smart brands combine them to generate more revenue

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In the last hour alone, I’ve opened and closed WhatsApp multiple times, checked my email, replied to a text, searched for a present for my niece’s birthday, and aimlessly clicked through an obscene amount of Instagram Stories. And this is all before 10 a.m. on a Tuesday.

Context switching is how we live. As a byproduct, we expect brands to show up where we are. But as a marketer, it can be tough to figure out the nuances of each channel and how to best use them together so they’re each living up to their revenue potential.

Here, we break down 3 major channels—email, SMS, and WhatsApp—and look at their strengths, personalisation potential, and use cases. By the end, you’ll have a clearer sense of which one is right for which moment, and how to use them together without overwhelming your audience or wasting your budget.

Marketing channels at a glance

Channel	Pricing model	Personalisation potential	Compliance considerations	Best for
Email	Volume-based pricing, cost-effective at scale	Dynamic content, segmentation, flexible design	Explicit consent and easy opt-out required	Newsletters, product education, onboarding flows
SMS	Cost per message	Dynamic fields, limited content	Explicit consent and easy opt-out required	Time-sensitive promos, alerts, abandoned cart nudges
WhatsApp	Per-message pricing, varies by country and message type	Rich media, carousels, real-time interaction	Strict Meta rules, explicit opt-in required, template approval	Conversational marketing, global audiences, support follow-ups

Now that you’ve seen how email, SMS, and WhatsApp stack up at a glance, let’s dig a little deeper. Each channel has its own strengths and quirks, and knowing when (and how) to use them can make all the difference.

Email

Email is a bit of a stalwart in the marketing world. It’s the comfortable blanket. The familiar face in the crowd. When you use it well, email gives you incredible reach, creative flexibility, and the power to build long-term customer relationships.

Where email wins

Massive reach at minimal cost

Most people have an email address. And, unlike paid ads or SMS, sending an email doesn’t cost more based on how many characters you use, how many people click through, or what country you’re targeting.

Flexible design and creative freedom

You’re not limited to plain text in an email. You can build beautiful designs to spotlight your products, use dynamic content blocks, embed images, and create immersive brand experiences. Regardless of the content, email is a great way to present it.

Automation and segmentation as smart ways to scale

With email, you can personalise at scale. You can create triggered flows, like welcome emails, abandoned cart reminders, or post-purchase messages. But most importantly, you can tailor your email automations to real-time customer behaviour and shifting preferences.

Where email falls short

Lower open rates

Email inboxes are chaotic. Even people who do want to hear from you might miss your message because it lands at the wrong time or gets buried under a dozen others.

Add to that the rise of email filters, and it’s even harder to break through the noise. You’re wrangling short attention spans, timing, and tab placement just to get your subject line read.

Inbox competition is fierce

You’re not just competing with other brands in email inboxes. You’re competing with receipts, shipping updates, work emails, calendar invites, bank alerts, and everything in between. Most inboxes are overflowing, and sometimes the default response is to skim, archive, or ignore.

Email marketing use cases

• Newsletters: Send useful, entertaining, or inspiring content.
• Welcome series: Tell your brand story, highlight your bestsellers, and maybe throw in a little discount to encourage that first purchase.
• Abandoned cart reminders: Nudge shoppers with a gentle reminder, product images, social proof, and a discount.
• Post-purchase follow-ups: Confirm orders, share shipping updates, and send educational guides.
• Win-back campaigns: Re-engage lapsed subscribers with a personalised offer.
• Product launches and back-in-stock alerts: Build hype, share the story behind a new product, and notify loyal customers when a popular item is back in stock.
• Review requests: Ask customers for feedback and images that can serve as social proof.
• Education and product tips: Share care instructions, styling guides, or recipe ideas.

💡 Real-life email use case: After using Klaviyo to create personalised welcome sequences, abandoned cart reminders, and post-purchase follow-ups, L. Eyes Eyewear now attributes 44% of their revenue to email marketing.

SMS

If email is your dependable long-form storyteller, SMS is your quick punchline. It’s fast, effective, and delivers some of the highest engagement rates in marketing. But with great power comes great responsibility, as well as a few caveats marketers need to be aware of.

Where SMS wins

High click rates

According to Klaviyo’s latest SMS marketing benchmark report, average SMS click rates for the top 10% of businesses are as high as 14.89%. This is because people actually read their texts and engage with their text inbox every day.

Immediacy

SMS is a real-time, immediate channel, and it’s perfect for time-sensitive promotions or anything that inspires immediate action. If your campaign hinges on urgency, SMS delivers the goods.

Concise value

You may only have 160 characters to work with (more if you use MMS), but you can pack a lot of value into a short message. And, when you use Klaviyo Data Platform, Klaviyo’s built-in customer data platform, you can personalise your messages with product recommendations, dynamic links, and discount codes for greater relevance.

Where SMS falls short

Strict compliance rules

To comply with regulations like the General Data Protection Regulation (GDPR) and the Telephone Consumer Protection Act (TCPA), you must get explicit consent before texting anyone. Opting out needs to be easy, trackable, and fast, which can feel like a hurdle if you don’t have the right tools.

Frequency considerations

Your texts live in the same space as family group chats, so SMS as a channel can feel intimate. You’ll need to be mindful of frequency when you text, although recent research from Klaviyo and Recharge found that 72% of consumers say a brand should send text messages at least once a week.

Keep in mind that SMS should complement other channels—you may want to launch big promotions via email and reserve a 24-hour last chance reminder via SMS, for example (more on this later).

Limited real estate

It’s a challenge to say something meaningful in 160 characters. But this is where personalisation comes in. When you can use customer data to tailor messages to recipients, you can pack in more value because the content of your texts reflects products they’ve browsed, for example.

SMS use cases

• Flash sale announcements: Share an upcoming 24-hour deal or weekend sale.
• Back-in-stock alerts: Notify shoppers that the item they were eyeing is finally available again.
• Abandoned cart nudges: Send a quick text reminder and a discount code.
• Shipping and delivery updates: Keep customers in the loop with real-time delivery alerts and tracking links.
• Personalised promo codes: Send a unique offer based on past purchases or loyalty status.
• Last-minute reminders: Use SMS as a final nudge before a sale ends, a product sells out, or a promotion expires.
• Event or appointment reminders: SMS is great if you’re running pop-ups, in-person fittings, or post-purchase services.
• Replenishment reminders: Send a friendly message to shoppers when it’s time to re-stock their consumables.
• Loyalty perks or VIP offers: Let your most engaged customers know when there’s something special just for them.

💡 Real-life SMS use case: Clothing brand Frances Valentine added SMS to only their highest-intent automations: abandoned check-out and back-in-stock. Revenue from these flows jumped 32% YoY in their first quarter as multi-channel flows. The brand also achieved a 21.8x return on investment from SMS in just 8 weeks.

WhatsApp

WhatsApp is the world’s most popular messaging app, with more than 3 billion monthly users. Similar to SMS, WhatsApp is where many people chat with friends, family—and, increasingly, brands.

Where WhatsApp wins

High engagement

Your WhatsApp message will be rubbing shoulders with chats from mom, the best friend, and the road trip group chat. As a result, engagement on WhatsApp is high.

Two-way conversations

WhatsApp nurtures two-way, ongoing conversations. Customers can reply, ask questions, browse a carousel of products, and complete a purchase, all within the same thread.

With Klaviyo’s Gorgias integration (launching soon), customers can even transfer from an automated chatbot to a live support agent with no awkward channel switching.

Rich media and personalisation

WhatsApp is so much more than a text. It supports rich, interactive formats that turn basic notifications into dynamic shopping and support journeys.

Here’s what you can include:

• Quick replies: Let customers respond with one tap.
• Call-to-action buttons: Add clickable actions like “Shop now” or “Track order” to drive instant engagement.
• Catalogs: Showcase full product collections in a chat thread so shoppers don’t have to leave the platform.
• Rich, branded templates: Design visually engaging messages that match your brand.
• Automated conversations: Set up smart, logic-based flows that guide people through FAQs, product recommendations, or purchase decisions.

Where WhatsApp falls short

Strict compliance rules

For WhatsApp (as with SMS), you need explicit opt-in from every subscriber. You also need to work with pre-approved message templates for any outreach that isn’t part of a 24-hour reply window. This is meant to protect the subscriber, but it also means more set-up and planning for you as a marketer.

WhatsApp messages fall into several categories:

• Marketing: These are promotional messages designed to drive awareness or sales, like product launches, special offers, abandoned cart nudges, or seasonal campaigns. You can only send them to people who have explicitly opted in to receive marketing content.
• Utility: Also known as transactional messages, these help customers stay informed about their orders or account activity. They include shipping updates, appointment reminders, order confirmations, and payment receipts.
• Support: These are service-related messages that help answer customer queries or resolve issues. They can be triggered when a customer reaches out or as part of a support thread handed off to a live agent.

Klaviyo handles everything from collecting compliant opt-ins to automatically selecting the right message template based on the type of communication you’re sending. Klaviyo also keeps track of the 24-hour reply window to make sure your messages meet Meta’s strict formatting and delivery rules.

Varied regional adoption

WhatsApp is the default mode of communication in many places, but it’s still fresh in certain markets. So you may not be able to scale WhatsApp as quickly as email or SMS—yet. That said, early adopters are a type of audience on their own, and you may be able to test bolder strategies as a result.

Meta’s interface

Meta Business Manager, template approvals, and compliance can be frustrating. But once you’re set up, the payoff is worth it—especially when you have a platform like Klaviyo handling the orchestration behind the scenes.

WhatsApp use cases

• Product quizzes and recommendations: Use quick replies to guide shoppers through an interactive quiz.
• Order and shipping updates: Keep all post-purchase information together in one thread.
• Customer support follow-ups: Combine automation and live chat to answer questions, resolve issues, or recommend products based on past purchases.
• Flash sales or limited drops: Give VIPs or engaged shoppers early access to special offers.
• Post-purchase care or tips: Send useful content after a purchase, like how-to videos, styling ideas, or just a simple thank-you message.

What you can expect for each channel

There’s no one best channel, just the best channel for the moment, the message, and the customer. Here’s how email, SMS, and WhatsApp stack up across the metrics that matter:

Engagement

Winner: WhatsApp and SMS

SMS and WhatsApp crush it when it comes to engagement. According to Klaviyo’s 2025 benchmark report, the average SMS click rate is 5.76%, whereas for email it’s 1.29%.

Notably, though, placed order rates are similar for email and SMS.

Cost efficiency

Winner: Email (with a caveat)

Email wins hands down on cost. You can reach thousands of people for a relatively low cost, which makes it the go-to channel for volume-based campaigns like newsletters, product drops, or educational content.

SMS and WhatsApp do cost more per message, but the upside is you’re often sending to highly engaged, high-intent audiences.

Personalisation

Winner: Email

Email offers the most flexibility with dynamic content, because you can do more with email design than you can with SMS. For example, you can send someone product recommendations based on website browsing behaviour, and you can pair that with social proof that matches each product.

SMS does support dynamic fields (like first names or unique discount codes), but there’s less room for complexity. WhatsApp is a bit of a middle ground. You can personalise, especially with carousels and quick replies, but you’re also working within Meta’s template rules, which means you have to plan ahead and stick to pre-approved formats.

Trust and loyalty

Winner: Depends on your strategy

Each channel builds trust in its own way.

Email is where you can share behind-the-scenes content, customer stories, values, and mission. SMS requires a more strategic approach. Too many texts and people will unsubscribe, but if you use it too sparingly, people may forget they subscribed and be confused when they hear from you.

WhatsApp is the most conversational of the 3 channels. It’s great for two-way conversations, customer support, and interactive experiences, like product quizzes and personalised recommendations.

The best strategy: how to orchestrate all 3 channels wisely

While it might feel like you have to choose between email, SMS, and WhatsApp, you don’t. In fact, the most effective marketing strategy orchestrates all 3 to work together based on what a customer actually needs in each moment.

This is where Klaviyo can give you an edge. Klaviyo B2C CRM was built as a unified, omnichannel platform from day one. That means every message you send is powered by a single customer profile and real-time data.

When your data is integrated across channels, it’s much easier to create multi-channel campaigns and automations that feel like one cohesive experience for the customer.

Think of each channel as playing a different role in the same customer journey. Let’s say someone looks at a product but doesn’t buy it. You may want to coordinate email, SMS, and WhatsApp as follows:

1. Email: Send a beautifully branded follow-up that explains product benefits, shares customer reviews, and addresses objections.
2. SMS: 24 hours later, if the subscriber hasn’t purchased, send a short, snappy text with a time-limited discount code.
3. WhatsApp: Still no action? Nudge them with a message that includes a product image, a quick-reply button for FAQs, or even a friendly check-in: “Need help deciding?”

The idea is that each channel builds on the last, using the customer’s previous behaviour to trigger what happens next.

Here are a few example journeys that combine email, SMS, and WhatsApp:

Abandoned cart recovery

1. Email: abandoned cart reminder with full product details
2. SMS (day 2): “Still thinking it over? Here’s 10% off for the next 12 hours.”
3. WhatsApp (day 3): product carousel with reply button that asks, “Have questions?”

Welcome series for new subscribers

• Email: primary welcome email with your brand story and product education
• SMS: quick thank-you text with a sign-up discount
• WhatsApp: interactive message with a quiz or “help me choose” options

Product launch campaign

• Email: full launch announcement and product details
• SMS (day of launch): “Now live! Shop before it sells out.”
• WhatsApp (post-purchase): thank-you message with support link and order updates

With Klaviyo, this all happens in one place. You can build automated flows that unfold in real time based on how a customer interacts with your previous messages.

The thing to remember here is that an omnichannel strategy doesn’t mean sending moremessages. It means sending the rightmessage on the rightchannel at the righttime.

Which channel should you choose?

Not sure where to start? Here’s the tl;dr:

• Start with email if you’re just getting going. It’s affordable, flexible, and perfect for building relationships at scale.
• Add SMS once you’re ready to drive action with time-sensitive promos, back-in-stock alerts, and quick reminders.
• Layer in WhatsApp when you’re ready to go deeper, with personalised, two-way conversations.

Customer journeys aren’t simple anymore. People bounce between email, SMS, and other channels before they ever hit “buy.” But when your marketing tools aren’t connected, it’s hard to know what’s actually working.

Klaviyo fixes that. The B2C CRM gives you a clear, customisable view of which messages and channels are driving results, all right where you already work. You can track performance across email, SMS, and WhatsApp, and understand where you should invest to see higher returns.