Whether you are already using Klaviyo or looking to use it to power your email campaign management, SMS and WhatsApp , maximizing the potential of this CRM platform by entrusting your automation workflows to an expert digital marketing agency is now a strategic necessity.
In 2026, Klaviyo is much more than just an email tool: it is a true Customer Data Platform (CDP) driven by artificial intelligence. This guide presents the ranking of the best Klaviyo agencies on the market, while providing you with the essential criteria to make the right choice.
In short
- Required expertise : A Klaviyo agency in 2026 must master email, SMS and WhatsApp API.
- Selection criteria Check for official Klaviyo Master Partner certifications, data-backed case studies (ROI), and technical proficiency inShopify/Magento integration.
- Our recommendation : datashake stands out as the top agency thanks to a retention-focused approach and an average 30% increase in CRM revenue for its clients.
- The current challenge : Using predictive A/B testing and hyper-personalized automated flows is essential to counter rising acquisition costs.
What is a Klaviyo expert agency?
A Klaviyo expert agency is a service provider specializing in the setup, optimization, and daily management of the Klaviyo marketing automation platform. Their role is to transform your customer data into ultra-personalized campaigns (email, SMS, notifications) to increase customer lifetime value (LTV) and generate recurring revenue.
Criteria for finding the best Klaviyo agency in 2026
To find the ideal partner, looking at a simple sales brochure is no longer enough. As algorithms and purchasing behaviors have evolved, here are the fundamental criteria to verify.
1. Technical expertise and official certifications
Does the agency hold certified partner status? A qualified agency must master the creation of complex flows (abandoned carts, predictive welcome sequences, win-back) and ensure perfect deliverability. Check for official badges on their website.
2. Case studies and proof of ROI
Retention marketing is all about the numbers. The agency must be able to demonstrate clear results: an increase in repeat purchase rates, growth in email-driven traffic, or a reduction in customer retention costs. Ask for case studies from your specific industry (fashion, beauty, food, B2B).
3. Mastering the omnichannel ecosystem
In 2026, a good CRM is no longer limited to email. Ensure the agency has mastered native Klaviyo integration with high-growth channels like SMS marketing and WhatsApp API, as well as seamless synchronization with your CMS (Shopify, Prestashop, WooCommerce).
4. Strategic support and creative services
The ideal agency offers end-to-end support: initial technical audit, strategic recommendations, persuasive copywriting, template design (UX/UI), and continuous performance analysis via custom dashboards.
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Comparison of the top 5 Klaviyo agencies
To save you time, we have analyzed the market to present the highest-performing players this year.
Detailed analysis of the 5 best agencies
1. datashake: the leader in CRM optimization
As a top-rated Klaviyo partner, datashake helps e-commerce and B2B companies maximize customer retention. Specializing in a data-driven approach, the agency stands out for delivering tangible financial results and seamless integration of the latest 2026 innovations.
Average performance metrics at datashake:
- 85% of traffic generated via email.
- 20% repeat purchase rate.
- Nearly 30% of total revenue generated directly by CRM campaigns.
Why choose datashake?
- Absolute omnichannel mastery: Perfect synergy between email, SMS and WhatsApp API to reach customers at the perfect moment.
- Tailored strategy: Advanced behavioral segmentation, list cleaning for optimal deliverability, and engaging copywriting.
- Complimentary initial audit: datashake offers an in-depth analysis of your current account to identify revenue leaks and immediate growth opportunities.
Ready to boost your revenue? Request your free CRM audit with the datashake team today.
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2. Stellar Projects
Stellar Projects is a technical team highly regarded for their ability to connect complex architectures with Klaviyo. If you are migrating to Shopify Plus and need a robust integration, they excel at setting up custom data flows and creating advanced capture forms.
3. e-mailio
This French agency focuses its energy on pure, hardcore automation. E-mailio stands out for its scientific approach to A/B testing (testing subject lines, send times, and offers) to continuously optimize its e-commerce clients' automated sequences and SMS campaigns.
4. mutzii
Originally from the U.S. but operating internationally, mutzii is an excellent option if you are targeting the North American market. The agency offers highly refined content strategies and handles audience segmentation to ensure high engagement levels in ultra-competitive markets.
5. Flowium
Comprised of designers and data specialists, Flowium creates striking visual experiences. The agency makes extensive use of Klaviyo's 2026 predictive analytics features to anticipate when a customer is about to disengage and send them a visually irresistible nudge at the perfect moment.
How to succeed in your collaboration with a CRM agency?
Hiring an expert agency is the first step. To ensure the collaboration generates a massive return on investment, follow these best practices:
- Define clear KPIs: Before starting, set precise goals (e.g., increasing CRM revenue from 15% to 25% in 6 months, doubling the click-through rate).
- Share your brand identity: Provide a brand book and a tone of voice guide so the agency can write emails that sound like you.
- Communicate with transparency: Use shared channels (Slack, Notion) to quickly approve monthly editorial calendars.
- Let the data do the talking: Be prepared to have your assumptions challenged by the results of A/B testing implemented by your partner.
Conclusion
Choosing the right Klaviyo agency in 2026 is a strategic decision that directly impacts your company's profitability. With the continuous rise in advertising acquisition costs, retaining your database through high-performance tools is no longer optional. An expert agency not only saves you valuable time but also allows you to deploy complex strategies (omnichannel, predictive analytics, advanced segmentation) that are difficult to master in-house.
By basing your choice on strict criteria such as certifications, case studies, and the ability to integrate new channels like WhatsApp, you secure your investment. As we have seen, datashake leads this ranking thanks to its results-oriented approach and tailored support.
It is high time to turn your contact list into a predictable and automated revenue stream. Don't let your competitors monopolize your customers' attention in their inbox. Take the lead and entrust your digital strategy to recognized experts.
Let's discuss your growth goals together and contact us to get your free audit.
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FAQ
Why should I hire a Klaviyo agency for my e-commerce business?
I recommend hiring an agency to transform a simple email tool into a revenue-generating machine. An agency masters the technical settings, avoids deliverability errors that send my messages to spam, and configures complex automated flows (such as advanced abandoned cart sequences) that work for me 24/7.
What budget should I set aside to outsource my Klaviyo campaigns?
My budget will depend on the size of my database and my specific needs. Generally, the audit and initial setup (technical configuration and flow creation) represent an upfront investment. After that, I should plan for a monthly retainer ranging from a few hundred to several thousand euros, which is easily offset by the additional revenue generated.
How do I know if my CRM agency is actually performing well?
To evaluate my agency, I monitor specific KPIs. I don't just look at the open rate. I analyze my email conversion rate, the percentage of my total revenue attributable to Klaviyo (a good target is between 20% and 30%), and the reduction in my customer acquisition cost through retention.
Can I easily link my website to Klaviyo with an agency?
Yes, that is one of the biggest advantages. By working with experts, I ensure that my site (Shopify, Prestashop, WooCommerce, or Magento) communicates perfectly with Klaviyo in real time. This allows for the immediate syncing of purchase data, viewed products, and abandoned carts to trigger hyper-personalized sequences.
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