Top Klaviyo Email Marketing Agencies: A Comparison Guide

If you are an e-commerce company that requires advanced, behavior-driven marketing automation and customer segmentation, Klaviyo is the platform for you. 

But to use its advanced features and truly unlock its potential, you need an expert by your side. 

We regularly get clients who tell us they didn’t realize they could do something with Klaviyo or that Klaviyo had a specific feature. By using the right Klaviyo agency, you’ll ensure your email campaigns are optimized, personalized, and delivering a high return on investment.

So, we created a guide that takes a closer look at a range of Klaviyo email marketing agencies. We aim to help you understand how these agencies operate so you can evaluate your options and find the right fit. 

How We Evaluated These Klaviyo Agencies 

To build a comparison, we first evaluated each agency against a set of factors that matter for ecommerce brands. 

Evaluation Criteria

Client Retention Rate

We looked at whether brands continue working with the agency over time. Strong retention often signals consistent results and long-term trust.

Case Study ROI

We focused on measurable outcomes — including revenue growth, flow performance, and email-attributed revenue — rather than surface-level metrics.

Certifications

Klaviyo Partner status was used as an indicator of platform expertise and technical capability.

Third-Party Ratings

We reviewed platforms like Clutch and Google to understand client feedback, review volume, and overall satisfaction.

Media Mentions & Recognition

Industry mentions, awards, and external validation were considered to assess credibility.

Breadth of Services

We evaluated whether agencies offer support beyond email, including SMS, lifecycle marketing, and retention strategy.

Team Structure & Expertise

We looked at team composition, specialization, and how agencies typically operate with clients.

A few notes before you compare

• This list highlights a selection of well-known Klaviyo agencies, but it doesn’t cover every capable team in the market
• Each agency included here stands out for its experience, track record, or focus within email and retention
• Your final decision should still be based on your specific goals, setup, and internal needs

Klaviyo Agencies – A Side-by-Side Comparison

To guide you through the process of choosing, we created a quick comparison table that breaks down (in detail) how these agencies differ in thei approach and areas of expertise.

A Closer Look at Each Agency

Here’s a more detailed breakdown of how each agency operates and who they’re best suited for.

1. InboxArmy

Best For: Brands that need hands-on Klaviyo execution, automation, and ongoing campaign support at scale

InboxArmy is a full-service email marketing agency for all of your email needs—from strategy and template creation to automation, segmentation, and campaign. Our data-driven approach has a proven track record of improving customer retention and driving lifetime value. With a track record of helping e-commerce brands boost revenue, we’re the go-to choice for businesses looking for hands-on Klaviyo expertise.

Clutch Rating: 4.9 (63 reviews)

Google Rating: 4.9 (35 reviews)

Founded: 2016 

Employees: 120+

What sets us apart?

InboxArmy stands out due to its extensive experience with Klaviyo’s advanced features. As Klaviyo Silver Master partners, our team comprises some of the industry’s leading email experts. Our ROI-driven strategies ensure that every campaign is optimized for success. We offer SMS and push notification services and serve over 25 industries. With a deep understanding of email deliverability and customer retention, InboxArmy ensures that every email sent delivers tangible results. 

You can learn more about our award-winning team and how we help businesses maximize engagement and conversions here, and see what our customers say about us here.

2. Underground Ecom

Best For: Fast-growing DTC brands focused on retention and maximizing customer lifetime value.

Underground Ecom is an email marketing agency that works only with fast-growing direct-to-consumer brands. They focus on keeping customers, not just getting them. As a Klaviyo Master Elite Partner, they use advanced email strategies and a strong tech stack to help businesses grow customer value over time. So far, they’ve helped generate more than $165 million in tracked sales for clients around the world.

Clutch Rating: – (0 reviews)

Google Rating: 4.6 (11 reviews)

Founded: 2017

Employees: 150+

What sets them apart?

What sets them apart is how narrowly they focus. Instead of trying to do everything, they specialize in retention and customer lifetime value. Their deep Klaviyo expertise shows in both their Elite Partner status and the results they deliver—like a 37% higher ROI than what most Klaviyo users see. With over 150 global clients and a 9.9 NPS score, they’ve earned industry awards, including Email Marketing Agency of the Year in 2021.
Their team includes more than 150 specialists across the globe, all focused on retention. They’re also part of Supergroup, a vetted network of top marketing agencies. While email is their main channel, they use a full stack of tools to support retention, always tailored to how DTC brands work and the challenges they face.

3. Hustler Marketing

Best For: Ecommerce brands looking for a fully managed, strategy-led approach with strong creative and data integration.

Hustler Marketing is a hands-on email marketing agency that builds custom strategies from scratch. They handle everything—campaign planning, design, automation, A/B testing, analytics, and deliverability. They don’t use templates. Instead, they mix creative work with deep data analysis to craft campaigns that match each client’s goals, audience, and industry. Their focus is simple: drive real, measurable results that matter to the bottom line.

Clutch Rating: 5 (14 reviews)

Google Rating: – (0 reviews)

Founded: 2018

Employees: 60+

What makes them different?

What makes them different is how tailored their approach is. They skip the one-size-fits-all playbook and build every strategy around the specific needs of each client. Every account gets a dedicated team.
They also run a detailed 7 to 10-day onboarding sprint that creates three key docs: a First Look Report that reviews performance, Copy Guidelines to match the brand voice, and Design Guidelines to keep visuals consistent. They’re certified across all major platforms like Klaviyo, Yotpo, Mailchimp, and HubSpot, which gives them the flexibility to work with whatever setup a brand is using. They’re also sharp on deliverability, optimization, and reporting, always tying results back to revenue—not just open rates or clicks.

4. UN/COMMON Agency

Best For: Brands prioritizing long-term retention, lifecycle marketing, and multi-channel growth (email + SMS).

UN/COMMON offers full-scale Klaviyo email marketing services built around long-term retention, not just short-term wins. They manage both email and SMS, and they go beyond basic campaigns to help e-commerce brands grow in a steady, profitable way. As a Klaviyo Master Elite Partner, they back their strategy with smart consulting and clear planning, using data to build stronger customer relationships across multiple channels.

Clutch Rating: – (0 reviews)

Google Rating: – (0 reviews)

Founded: 2015

Employees: 45

What sets them apart?

What makes them different is how deeply they focus on sustainable growth. They don’t follow the churn-and-burn model that pushes quick sales. Instead, they create lifecycle marketing programs that include loyalty systems, subscription management, and real technical support—complete with in-house experts on deliverability and compliance. Their campaigns don’t stop at email and SMS. They reach customers wherever they’re most active, and that multichannel approach has helped clients triple their repeat purchases.
UN/COMMON blends strategy with action. They treat subscribers like VIPs, using custom offers and messaging that feels personal and relevant. Their work is grounded in data, but tailored to each brand’s market and business goals. Every recommendation is specific, thoughtful, and built to last.

5. Andzen

Best For: Ecommerce brands that want advanced Klaviyo automation, segmentation, and customer journey planning.

Andzen is a Klaviyo-focused email marketing agency that builds custom customer journeys for B2C brands. They’re the first Klaviyo Master Elite Partner in the APAC region and the fifth worldwide. That status reflects deep experience with Klaviyo’s CRM tools, especially for eCommerce.

Clutch Rating: – (0 reviews)

Google Rating: 4.8 (19 reviews)

Founded: 2014

Employees: 10-20

What makes them different?

Andzen’s Master Elite Partner status gives them access to features and support that most agencies don’t get. Their team knows how to get more out of Klaviyo—using segmentation, behavior tracking, and automation to build smarter email flows. They don’t just send emails. They plan full journeys that connect with customers at the right time. Their work regularly beats industry benchmarks in open rates, clicks, revenue per recipient, and ROI. And instead of just chasing one-off sales, they focus on long-term customer relationships that grow brand loyalty.

6. No Limit Email

Best For: DTC brands looking to improve email design and combine strong creative with performance-driven strategies.

No Limit Email is a results-driven Klaviyo email marketing agency that specializes in DTC brands and customer retention strategies. Their expert strategies and strong creative direction have given their clients an easily apparent upgrade to their emails.

Clutch Rating: 5 (21 reviews)

Google Rating: – (0 reviews)

Founded: 2020

Employees: 15-30

What sets them apart?

What makes No Limit Email unique is how skilled they are in up-leveling the email design of all of their clients. Their creative team brings a strong visual direction to every campaign. Their data-driven approach has led to a proven track record in revenue growth for DTC clients.

7. DIDO Agency

Best For: Brands that want structured onboarding and fast performance improvements through advanced segmentation.

DIDO Agency is known for its performance-focused Klaviyo email marketing services. They have a highly refined client-onboarding process that helps their customers rapidly optimize their email marketing over six months. As Klaviyo partners, DIDO helps e-commerce brands stand out from their competition and drive revenue.

Clutch Rating: 4.8 (6 reviews)

Google Rating: 4.9 (18 reviews)

Founded: 2017

Employees: 25+

What makes them different?

Their highly optimized onboarding experience helps clients see rapid improvements within six months. As a Klaviyo Master Platinum Partner, they leverage advanced segmentation and pre-built integrations to give their customers advanced data analytics and segmentation.

8. Chronos Agency

Best For: Scaling ecommerce brands focused on retention, lifecycle marketing, and increasing customer lifetime value.

Chronos Agency is a Klaviyo Master Elite partner that specializes in increasing customer lifetime value and retention for e-commerce brands. They create tailored retention strategies that drive repeat purchases for their clients and have a strong history of improving ROI and retention.

Clutch Rating: 4.8 (44 reviews)

Google Rating: – (0 reviews)

Founded: 2017

Employees: 80+

What sets them apart?

Chronos’s strength is their data-driven email nurture strategies. They create 100% custom email content tailored to the specific needs of each brand, which helps cultivate long-term customer engagement and growth.

9. The Email Marketers

Best For: High-growth ecommerce brands (8–9 figure) looking for data-driven campaigns and multi-channel retention support.

The Email Marketers is a team of Klaviyo experts who specialize in crafting high-converting email campaigns for rapidly growing e-commerce brands earning 8 or 9 figures. They use AI-driven data to be one of the leaders in retention marketing. Their services include SMS, direct mail, campaign and subscription management, and loyalty programs.

Clutch Rating: 5.0 (4 reviews)

Google Rating: 5.0 (7 reviews)

Founded: 2017

Employees: 10-50

What makes them different?

Their expertise in high-performing Klaviyo campaigns is driven by two major factors: gathering insights through AI-driven data and utilizing A/B testing to optimize email performance. Their broader service offerings make The Email Marketers comprehensive partners for retention marketing. 

10. Fuel Made

Best For: High-growth ecommerce brands (8–9 figure) looking for data-driven campaigns and multi-channel retention support.

Fuel Made is an ecommerce marketing agency that helps Shopify brands grow through advanced Klaviyo email and SMS strategies. They focus on using data, design, and automation to build emails that connect with customers and drive sales.
Their team includes strategists, writers, designers, and developers who work together to spot the biggest growth opportunities and build custom plans around them. As a Klaviyo Professional Partner and Shopify Plus Partner, they’ve earned a reputation for delivering clear results in a space that often overpromises.

Clutch Rating: 5.0 (20 reviews)

Google Rating: – (0 reviews)

Founded: 2000

Employees: 10-25

What sets them apart?

What makes them different is how focused they are. They’ve been working only with Klaviyo since 2016, and their team is made up of senior-level experts in every area of email marketing. Clients often stay with them for years, thanks to their mix of smart strategy and strong creative work.
They also stand out for how closely they connect email with ecommerce. Their dual expertise in Klaviyo and Shopify means they can create smooth, integrated experiences that actually convert. Their reporting is straightforward, with real numbers tied to performance—like doubling campaign revenue or boosting welcome series order rates by over 100%.

How to Decide Among the Best Klaviyo Email Marketing Agencies?

Before you call agencies, make sure you know what you want to fix. Do you need more repeat customers by using RFM segmentation? Better ways to get people to leave their carts? A strategy for the whole lifecycle?

The worst thing you can do is say “we need better email marketing” without going into detail. This causes expectations to be out of line and money to be wasted.

Here are the steps to choosing from the list above:

• Your Goals: Be specific about what you need – flows, campaigns, SMS, segmentation, or full lifecycle support.
• Your Shortlist: Focus on 3–5 agencies that work with brands similar to yours in size and industry.
• Their Expertise: Look for real results, revenue impact, flow performance, and proven Klaviyo experience.
• Their Approach: Pay attention to how they think. Strong agencies ask about your business, not just pitch services.
• Proof of Work: Review actual examples, welcome flows, win-backs, segmentation strategies, and results.
• Your Budget: Pricing varies widely. Focus on value and ROI, not just the lowest cost.

Moving Forward

• Narrow it down to a few agencies that feel aligned
• Use conversations to understand how they think
• Compare based on fit, not just pricing
• Choose the one that makes the most sense for your goals

Looking Beyond The List?

The agencies covered here are a strong starting point, but they’re not the only options available.

Depending on your needs, you might find a better fit by exploring beyond this list. A few good places to look:

• Klaviyo’s partner directory
• Platform-specific partner networks
• Referrals from brands in your space
• Industry communities and peer groups
• Ecommerce and DTC-focused forums

Final Thoughts

Working with a Klaviyo-focused agency can help ecommerce brands get more from their email marketing. But it’s not just about knowing the platform. You need a partner who understands strategy, knows how to create strong campaigns, and uses data to keep improving results.

The best agencies don’t stop at basic emails. They build advanced automations, use smart segmentation, and create personalized customer journeys that lead to real revenue. They also keep things transparent with clear reporting and results you can track.

If you’re looking for a partner with hands-on Klaviyo expertise and a strong focus on execution, InboxArmy is one option worth considering.

Frequently Asked Questions

1. What is the average cost of hiring a top Klaviyo email marketing agency?

Hiring a Klaviyo email marketing agency can cost anywhere from $500 to over $5,000 per month. It depends on what you need – simple email flows or a full strategy across your customer lifecycle. Agencies usually charge in one of three ways:

• a monthly retainer
• a cut of the revenue they help generate
• or a flat project fee.

If you’re just getting started, you can also expect to pay a one-time setup fee in the first month.

2. What questions can you ask before onboarding with your Klaviyo agency?

Don’t just ask the usual scoping questions. Get specific and dig deeper into their Klaviyo expertise. Here are some questions to ask:

Start with their credentials:

• Are you a Klaviyo Master Elite Partner?
• How many brands like mine have you worked with?
• Can you show real examples of Flows you’ve built?

Dig into the strategy:

• Which Klaviyo Flows do you recommend for my type of business – welcome series, browse abandonment, win-backs?
• How deep do you go with segmentation beyond just age or location?
• Do you actually use Klaviyo’s predictive analytics and Smart Sending, or do you mostly stick to the basics?

Get technical

• How will you set up a particular integration and keep my data in sync?
• Out of Klaviyo’s 350+ integrations, which ones do you actually use and why?
• What’s your track record with Klaviyo SMS, and do you know how to make it work alongside email?

Talk about measurement:

• How do you track revenue attribution inside Klaviyo?
• What’s your process for A/B testing Flows versus campaigns?
• And how often do you go back and tweak my automation triggers to improve results?

The right agency will never shy away from talking about Klaviyo’s features and how they’d use them for your brand. If they treat Klaviyo like any other email tool, it’s a red flag. Keep looking.