Every ecommerce marketing team is running at least two of these three channels. The question isn’t whether to use email, SMS, or WhatsApp – it’s how to allocate your time, budget, and attention across them.
This is an honest breakdown of where each channel wins, where it falls short, and what the data says about performance.
Open Rate Comparison
This is the statistic that usually starts the conversation:
| Channel | Average Open Rate |
|---|---|
| 85–95% | |
| SMS | 90–98% |
| 20–40% |
WhatsApp and SMS have comparable open rates because both deliver notifications to the phone’s lock screen and notification bar. People read text messages and WhatsApp messages almost reflexively. Email, even with a good sender reputation and subject line, competes in a crowded inbox environment where selective reading is the norm.
The high open rate for WhatsApp and SMS doesn’t automatically translate to better campaign performance – what you do after the open matters enormously. But it does mean your message is more likely to be seen.
Engagement and Response Rates
Open rates are a starting point. The more meaningful metric is what happens after someone reads your message.
WhatsApp enables two-way conversation. A customer who receives a cart recovery message can immediately reply with a question – about sizing, delivery time, a return policy – and get an answer before abandoning their interest. This conversational dynamic is unique to WhatsApp and meaningfully increases conversion rates beyond what you’d predict from open rates alone.
SMS has high open rates but limited interactivity. Response rates to SMS marketing messages are typically 5–10% for engagement, and conversations feel more formal and limited. Rich messaging (RCS) is improving this, but it’s not yet universally available.
Email enables long-form content, images, and complex CTAs, but response rates are low. Most email marketing success comes from driving click-throughs to your website, not from email conversations.
Cost Per Message
| Channel | Typical Cost Per Message |
|---|---|
| ~$0.001–$0.01 (via ESP monthly plan) | |
| ~$0.02–$0.10 per conversation (Meta fees + platform) | |
| SMS | ~$0.01–$0.05 per message (higher in some markets) |
Email wins on cost per message for high volumes. An email ESP that handles 50,000 sends per month typically costs less on a per-send basis than WhatsApp or SMS.
However, cost per message is the wrong metric for channel comparison. The metric that actually matters is cost per recovered order or cost per converted customer.
When you account for conversion rates:
- A WhatsApp cart recovery message that costs $0.05 and converts at 25% has a cost per recovery of $0.20.
- An email that costs $0.005 and converts at 5% has a cost per recovery of $0.10.
Email looks cheaper – but only if your traffic has equally high purchase intent. Email lists typically contain many subscribers who haven’t bought in months or years. WhatsApp lists contain people who opted in recently and are actively engaging. The quality differential often makes WhatsApp more cost-effective in practice, even though the per-message cost is higher.
Deliverability
Email has a significant deliverability problem at scale. Getting messages into the primary inbox – not Promotions, not Spam – requires ongoing sender reputation management, list hygiene, engagement monitoring, and technical setup (SPF, DKIM, DMARC). Even well-managed email programs see 10–15% of messages never reach the inbox.
SMS deliverability is generally strong in markets with reliable carrier infrastructure. The main issues are carrier filtering for spammy content and number quality.
WhatsApp deliverability is very high for messages sent through the official API. Messages either arrive or they don’t (and you know which). There’s no spam folder, no Promotions tab. The main risk to deliverability is having your number restricted due to poor quality signals (high block rates), which is why compliance and audience quality matter.
Opt-In Requirements and List Building
| Channel | Opt-In Requirement |
|---|---|
| Required in most regions (GDPR, CAN-SPAM, CASL, etc.) | |
| SMS | Required in most regions; often requires double opt-in |
| Required; enforced at the platform level |
All three channels require opt-in in most jurisdictions, but the enforcement mechanisms differ. Email and SMS violations primarily carry legal/regulatory risk. WhatsApp violations result in your business number being restricted or banned by Meta directly – making platform enforcement more immediate.
The upside of the WhatsApp opt-in requirement is that it forces list quality. Because you can’t buy a list or add contacts without consent, every subscriber actively chose to hear from you. This is why engagement rates are so much higher.
What Each Channel Does Best
Email excels at:
- High-volume, low-cost outreach to large lists
- Long-form content (newsletters, product guides, lookbooks)
- Sequences with many touches (5–10 email drip campaigns)
- Markets where WhatsApp penetration is lower (Japan, South Korea, US)
- Audiences that prefer asynchronous, lower-urgency communication
SMS excels at:
- Ultra-urgent messages (flash sales ending in hours, appointment reminders)
- Markets where WhatsApp isn’t dominant but mobile is primary
- Audiences who prefer minimal-interface messaging
- Short, high-urgency CTAs
WhatsApp excels at:
- Markets where it’s the primary messaging app (most of the world)
- Two-way conversations (support, pre-purchase questions, post-sale service)
- Cart and checkout recovery
- High-intent, warm audiences (opted-in buyers, not cold leads)
- Building a long-term direct channel to your best customers
A Realistic Multi-Channel Strategy
The stores with the most effective messaging strategies don’t choose one channel – they use each for what it does best:
- WhatsApp as the primary recovery channel and direct customer relationship layer
- Email for high-volume campaigns, newsletters, and audiences who haven’t opted into WhatsApp
- SMS for ultra-urgent alerts or in markets where WhatsApp penetration is low
If you’re currently running email-only and adding WhatsApp, the fastest path to ROI is setting up the cart recovery automation first. That single automation, running on top of your existing Shopify or WooCommerce traffic, typically generates enough recovered revenue to justify the platform cost many times over.
From there, building the campaign layer – sending promotional WhatsApp messages to your opted-in subscriber list – compounds the ROI over time as your list grows.
Vuelve provides WhatsApp marketing, cart recovery, and support tools for ecommerce teams – built on the official WhatsApp Business API. Compare plans.