Klaviyo and Omnisend fight over email. Remery skips email retention entirely for WhatsApp, where open rates run 3-6x higher. Here's the honest comparison.
TL;DR
- Klaviyo and Omnisend are both email-first platforms - Klaviyo wins on automation depth and predictive analytics, Omnisend wins on price and multi-channel breadth (email + SMS + push).
- Remery isn't an email platform at all. It's an AI agent that runs customer retention on WhatsApp, where open rates average 90-98% versus 15-25% for email (Meta for Business, 2025).
- The honest comparison isn't three email tools - it's "email, done well" (Klaviyo or Omnisend) vs "skip the inbox and message customers where they actually read things" (Remery).
- Many merchants run both: Klaviyo or Omnisend for newsletters and broadcast campaigns, Remery for the highest-value retention moments (abandoned cart, post-purchase, win-back) where the extra open-rate matters most.
Shopify merchants comparing "Klaviyo vs Omnisend vs Remery" are usually really asking one of two different questions, and conflating them leads to a worse decision either way.
Question one: "Which email platform should I use?" That's Klaviyo vs Omnisend - two mature, email-first tools competing on automation depth, price, and multi-channel reach.
Question two: "How do I actually get customers to open and act on retention messages?" That's a different question, and it's the one Remery answers - not with a better email builder, but by moving the highest-value retention messages (cart recovery, post-purchase check-ins, win-back offers) off email entirely and onto WhatsApp, where open rates are dramatically higher.
This comparison covers both questions honestly, because most Shopify stores need an answer to each.
| Klaviyo | Omnisend | Remery | |
|---|---|---|---|
| Primary channel | Email (+ SMS) | Email + SMS + push | WhatsApp (AI-run retention agent) |
| Open rates (industry average) | 15-25% | 15-25% (email) | 90-98% (WhatsApp) |
| Best for | Complex email flows, DTC brands | Multi-channel SME merchants on a budget | Merchants who want retention messages actually read and acted on |
| Shopify integration | Deep (native) | Deep (native) | Deep (native via Shopify app) |
| Campaign building | You build flows in a visual editor | You build flows in a visual editor | You describe the goal; the AI agent builds and runs the sequence |
| Starting price | Free (250 contacts) | Free (250 contacts) | Free tier available |
Email marketing is still a genuinely strong channel - DMA's 2025 benchmark puts average ROI at £36-£42 per £1 spent. But that ROI is diluted by a structural problem: most marketing email never gets opened. Industry average open rates across ecommerce sit at 15-25%, and even well-run flows rarely clear 35-40%.
WhatsApp doesn't have that problem. Meta's own business messaging data puts WhatsApp open rates at 90-98%, and because it's a messaging app rather than an inbox competing with dozens of other senders, messages get read within minutes, not days.
That gap is the entire reason Remery exists as a separate category from Klaviyo and Omnisend rather than a third competitor in the same one. It's not a claim that email is dead - it's a bet that the highest-value, most time-sensitive retention messages (an abandoned cart, a delivery check-in, a win-back offer with an expiry) deserve the channel where they'll actually be seen.
Klaviyo is, for many Shopify merchants, the default assumption when they think about retention marketing. It's dominant in DTC ecommerce and earned that position through genuine depth.
What Klaviyo does well: a granular customer data model (every order, page view, email interaction tracked), a best-in-class visual flow builder for conditional automation, and predictive analytics that estimate lifetime value and churn risk.
Where it falls short: pricing scales steeply with list size (around £400/month at 50,000 contacts for email alone), it rewards significant time investment to use properly, and - like every email platform - it's still bound by email's open-rate ceiling no matter how well the flow is built.
Omnisend targets the merchant who wants email, SMS, and push notifications in one platform rather than stitching several together, at a price that undercuts Klaviyo considerably.
What Omnisend does well: genuinely useful pre-built automation templates (abandoned cart, welcome series, post-purchase), solid cross-channel sequencing, and roughly half of Klaviyo's price at 10,000 contacts.
Where it falls short: shallower segmentation and predictive modelling than Klaviyo, and SMS delivery quality that varies by region - UK merchants should verify local SMS support before committing. It's still an email-first tool with the same open-rate ceiling as Klaviyo.
Remery takes a different approach to the same underlying goal - keeping customers coming back - by moving retention messaging onto WhatsApp and having an AI agent run it end-to-end.
Conversational setup, not flow-building. Instead of configuring triggers and branches in a visual editor, you describe the outcome: "message customers who haven't ordered in 90 days with a personalised offer." The AI builds and runs the sequence, timed to each customer's own order history.
AI-native personalisation. Message content adapts per customer - product recommendations, timing, and tone based on purchase history and behaviour, not just a first-name merge field.
Built for the moments that matter most. Abandoned cart recovery, post-purchase care, and win-back sequences are exactly the messages where a 90%+ open rate compounds into materially more recovered revenue than the same sequence sent by email.
Where it's still growing: Remery is newer than Klaviyo or Omnisend, so it doesn't have their years of community templates and agency expertise. And because WhatsApp is a messaging channel, it isn't the right tool for a monthly newsletter or broad brand-awareness broadcast - that's still email's job.
Klaviyo if you have a significant list (10,000+), the team to build sophisticated flows, and email is your primary revenue channel.
Omnisend if you want email, SMS, and push in one affordable platform and don't need Klaviyo's full predictive depth.
Remery if you want the moments that actually drive repeat purchase - cart recovery, post-purchase, win-back - sent somewhere customers will genuinely see them, run by an AI agent rather than a flow you have to build and maintain yourself. See how it works on the WhatsApp retention marketing page.
Most stores, honestly: Klaviyo or Omnisend for newsletters and broad campaigns, Remery layered in for the highest-value 1:1 retention sequences. They're not mutually exclusive - they solve different problems.
Is Remery an email marketing platform? No. Remery runs customer retention on WhatsApp, not email. If you need a newsletter or broadcast email tool, Klaviyo or Omnisend are the right category - Remery is built specifically for high-open-rate, AI-personalised retention messaging.
Can I use Klaviyo or Omnisend alongside Remery? Yes, and many merchants do. Keep your existing platform for newsletters and broad campaigns, and use Remery for time-sensitive retention moments where WhatsApp's open-rate advantage matters most - abandoned carts, post-purchase check-ins, and win-back offers.
Why is WhatsApp's open rate so much higher than email's? WhatsApp is a messaging app people check throughout the day, not an inbox competing against dozens of other marketing senders. Meta's business messaging data puts WhatsApp open rates at 90-98%, versus 15-25% industry-average for ecommerce email.
Is Omnisend good enough to replace Klaviyo for email? For most Shopify stores under roughly 50,000 contacts with standard automation needs, yes - the gap that matters (predictive CLV, granular segmentation) is primarily valuable for larger, data-rich stores.
Does switching to WhatsApp mean giving up email entirely? No. The strongest setups keep email for broad reach and use WhatsApp for the specific, high-value retention moments where a customer's attention is worth the most.
Klaviyo and Omnisend remain the strongest choices if the question is "which email platform" - Klaviyo for depth and scale, Omnisend for value and multi-channel breadth. But if the real question is "how do I get retention messages actually read," email - any email platform - has a structural open-rate ceiling that WhatsApp doesn't share.
Remery isn't trying to out-build Klaviyo's flow editor. It's built around a simpler bet: an AI agent messaging customers on WhatsApp, at 90%+ open rates, will recover more abandoned carts and win back more lapsed customers than the same sequence sent to an inbox. See it in action on the Remery WhatsApp marketing page.