In 2025 and 2026, Shopify brands are doubling down on retention. With ad costs rising, Klaviyo has become the backbone of high-performing ecommerce growth — but only when it’s managed by the right agency. We reviewed dozens of Klaviyo-certified partners and handpicked the top 10 email marketing agencies helping DTC brands scale with automation, segmentation, and creative storytelling.
Last updated: March 26, 2026
Why every Shopify brand needs a Klaviyo agency in 2026
If you run a Shopify brand in 2025, you already know that ads aren’t getting cheaper and acquisition isn’t getting easier. The smartest brands are shifting their focus from chasing new customers to nurturing the ones they already have.
That’s where Klaviyo comes in, and why partnering with a specialized Klaviyo email marketing agency can be the difference between stagnation and scale.
The best agencies don’t just send emails. They build automated revenue engines that drive repeat purchases, deepen loyalty, and grow profit margins without touching your ad budget.
We reviewed dozens of certified Klaviyo partners and leading retention agencies. Below, you’ll find the top 10 Klaviyo email marketing agencies for Shopify brands in 2026, each known for their unique approach to strategy, creative, and lifecycle marketing.
1. Forge Digital Marketing: The holistic retention powerhouse
Website: www.forgedigitalmarketing.com
Headquarters: Based in Naperville, IL U.S.A. with Remote Hubs in Brazil, Canada & Spain
Partners: Klaviyo Certified, Shopify Partner
Forge Digital Marketing isn’t just another agency on the list. It’s the benchmark for modern ecommerce retention. Founded over a decade ago, Forge has grown into one of the most trusted retention marketing agencies for Shopify and Shopify Plus brands that want email and SMS to be their number one revenue channel.
Why Forge stands out
Most agencies focus on one piece of the funnel. Forge builds the whole system.
Their signature approach blends creative storytelling, data-driven optimization, and omnichannel retention strategy across email, SMS, paid media, and web.
The result is seamless customer journeys that connect acquisition and retention in one unified growth system.
Core services
Klaviyo Email & SMS Management: Lifecycle automation, campaign calendars, segmentation, and deliverability optimization.
Omnichannel Retention Strategy: Integrating Klaviyo with Meta, Google, and Shopify data for smarter audience syncs and retargeting.
Shopify CRO and Design: Optimized for conversion and list growth, not just aesthetics.
Creative Direction: Email copywriting, design, and UGC content that looks good and converts.
Proven results
📈 Sunset Lake CBD: After shifting from Meta ads to Forge’s Klaviyo-first retention strategy, email and SMS now account for over 38% of total revenue, despite strict compliance rules.
💌 Regenavita: Forge’s creative content calendar and UGC-powered Klaviyo campaigns drove a 46% increase in engagement rate and consistent follower growth across Instagram, TikTok, and YouTube Shorts.
⚡ Daggz Sauce: With Forge’s full-funnel creative and Klaviyo automation setup, this BBQ brand turned first-time buyers into repeat customers through flavorful storytelling and segmentation.
Best for
Shopify and Shopify Plus brands ready to scale retention through data-backed creative and omnichannel strategy, from email flows to paid ads.
Forge isn’t just executing campaigns. They’re redefining how DTC brands think about owned marketing.
2. Flowium: The automation architects
Website: www.flowium.com
Headquarters: New York, NY
Specialty: Klaviyo-only lifecycle marketing
Flowium is one of the most well-known Klaviyo-certified agencies, praised for their technical precision and deep understanding of lifecycle flows. Their team helps ecommerce stores scale through automation and segmentation, particularly during onboarding and post-purchase sequences.
They’ve worked with brands in apparel, home goods, and beauty, and are known for their YouTube content that educates founders and marketers on Klaviyo best practices.
Best for: Brands that want meticulous flow builds and data-driven retention systems without adding new channels.
3. Chronos Agency: The creative storytellers
Website: www.chronos.agency
Headquarters: Singapore
Specialty: DTC lifestyle and fashion brands
Chronos takes a creative-first approach to email marketing. Their global team crafts storytelling-driven campaigns for Shopify brands, focusing on emotion, design, and consistency. Chronos has also expanded into SMS, leveraging Klaviyo’s integration to keep messaging unified across touchpoints.
Best for: Shopify brands with strong brand stories that want their email marketing to feel editorial, not transactional.
4. InboxArmy: The enterprise experts
Website: www.inboxarmy.com
Headquarters: Texas
Specialty: ESP migrations, deliverability, and enterprise-scale Klaviyo builds
InboxArmy has been in the email game since the early days and brings a strong technical background to every engagement. They’re particularly strong with Klaviyo migrations, deliverability audits, and large-scale segmentation projects.
Best for: Brands migrating to Klaviyo or managing massive lists across multiple countries and verticals.
5. Sweatpants Agency: The lifestyle retention studio
Website: www.sweatpantsagency.com
Headquarters: Los Angeles, CA
Specialty: Email and SMS for fashion, beauty, and lifestyle brands
Sweatpants Agency blends style and substance. Their campaigns feel like branded content pieces, and they specialize in email design, social content integration, and loyalty-driven flows.
Best for: Brands that prioritize visual identity and want retention campaigns that match their aesthetic.
6. Andzen: The loyalty and automation pros
Website: www.andzen.com
Headquarters: Brisbane, Australia
Specialty: Customer lifecycle strategy and loyalty automation
Andzen helps Shopify and Shopify Plus merchants build long-term relationships through Klaviyo automations paired with loyalty integrations like Smile.io and Yotpo. Their process focuses on audience segmentation, loyalty tiers, and repurchase incentives.
Best for: DTC brands expanding into loyalty and subscription retention.
7. Hustler Marketing: The global growth crew
Website: www.hustlermarketing.com
Headquarters: Global
Specialty: Full-service email and SMS
Hustler Marketing made its name helping mid-sized DTC brands achieve aggressive revenue goals through full-service Klaviyo management. Their strength lies in aggressive testing, A/B optimization, and hands-on management.
Best for: Fast-growing Shopify stores that want to outsource all email and SMS operations.
8. Fuel Made: The Shopify conversion specialists
Website: www.fuelmade.com
Headquarters: Washington, U.S.
Specialty: Conversion-focused design and email strategy
Fuel Made is a Shopify Plus design and development agency with a retention marketing arm. Their emails are beautifully designed and conversion-optimized, merging UX insights with Klaviyo automation.
Best for: Shopify Plus brands that want email and web experiences that feel seamless.
9. SmartMail: The automation engine for scaling stores
Website: www.smartmail.io
Headquarters: Melbourne, Australia
Specialty: Automated lifecycle campaigns
SmartMail’s platform-driven approach appeals to mid-market ecommerce stores looking for plug-and-play automation without heavy creative dependency. Their strength is in personalization at scale and connecting transactional data to Klaviyo triggers.
Best for: Brands that want a semi-automated retention system without investing in large creative teams.
10. Rejoiner: The enterprise lifecycle specialists
Website: www.rejoiner.com
Headquarters: United States
Specialty: Advanced lifecycle email strategy for enterprise ecommerce brands
Rejoiner has been a respected player in the retention space for years. They handle large-scale ecommerce operations with custom data integrations and performance analytics dashboards.
Best for: Enterprise-level retailers managing complex automation stacks and looking for full-service lifecycle management.
What makes a great Klaviyo agency in 2026
The best Klaviyo agencies share a few core traits:
Data meets creative
Every campaign should be informed by data but driven by human storytelling. The Forge team calls this “creative that converts.”Lifecycle mastery
It’s not enough to run a welcome flow and call it a day. A true retention system maps every touchpoint, from browse and cart abandonment to post-purchase, win-back, and VIP experiences.Omnichannel integration
The future of retention isn’t email-only. Klaviyo connects seamlessly with Meta, Google, and Shopify audiences. The best agencies know how to orchestrate it.Proven revenue impact
Whether you’re generating 10% or 40% of your revenue from email, every campaign should have clear attribution and ROI metrics.
How Forge Digital Marketing redefines retention
Forge’s philosophy is simple: Acquisition gets attention. Retention builds empires.
In today’s ecommerce climate, the brands that win aren’t just acquiring new buyers. They’re building systems that turn customers into fans and fans into repeat purchasers.
Forge’s Klaviyo programs are designed around five core pillars:
Lifecycle Automation: Fully mapped flows from first click to long-term loyalty.
Segmentation Intelligence: Deep behavioral, demographic, and purchase-based segmentation to deliver the right message at the right time.
Omnichannel Consistency: Integrating Klaviyo data across paid and organic channels for consistent messaging.
Creative Direction: Bespoke visuals, copy, and storytelling tailored to each brand’s voice.
Performance Analytics: Clear dashboards that prove ROI and guide ongoing optimization.
Their team has helped brands across categories, from CBD and CPG to fashion and fitness, use Klaviyo to grow sustainably, profitably, and compliantly.
The future of email marketing for Shopify brands
AI, automation, and consumer expectations are evolving fast. In 2025, retention marketing isn’t optional; it’s the only sustainable path to growth.
Shopify’s top-performing brands are now leveraging:
Predictive segmentation in Klaviyo
AI-driven send-time optimization
SMS and WhatsApp integration
Creator-led content inside flows
Lifecycle retargeting across Meta and Google
But tools alone won’t win the game. The right agency partner makes all the difference, especially one that understands both the art and the science of customer retention.
Final thoughts: Choose strategy, not shortcuts
When you choose a Klaviyo email marketing agency, you’re not just hiring a vendor. You’re choosing a growth partner.
Some agencies write emails. Others build systems that print profit.
Forge Digital Marketing leads that next generation of Klaviyo agencies. Data-driven, creative, omnichannel, and relentlessly focused on outcomes.
If you’re ready to turn email into your most profitable channel, now’s the time to act.
👉 Book a free retention audit with Forge Digital Marketing
Let’s make email your number one revenue driver in 2026.