The Top 7 Klaviyo Agencies to Help You Build a Stronger Retention Machine

Klaviyo is the lifeblood of retention for almost every serious ecommerce brand today.

Email, SMS and push notifications are all crucial parts of your marketing stack. It’s no longer viable to grow a sustainable brand on aggressive acquisition alone. You need to be making the most out of these direct communication channels, in order to make up the margins that rising CACs are steadily eating up.

You have two choices for how to approach this. Run your retention marketing in-house, or contract a Klaviyo agency to handle it for you.

This article is for those who want to go down the second path.

The Best Klaviyo Agencies for Retention-First Ecommerce Brands

Here are some of the top agencies to check out, if you’re looking for someone to own your Klaviyo strategy.

1. InboxArmy

InboxArmy stands out as a top U.S. email marketing agency specializing in deliverability, automation, and large-scale campaign management. Based in Grapevine, Texas, and founded in 2016, they’ve managed campaigns for over 5,000 brands across 25+ industries, including ecommerce, SaaS, and healthcare.

Their expertise lies in combining technical precision with creative strategy. InboxArmy conducts domain and IP audits, authenticates senders with SPF, DKIM, and DMARC, and warms IPs for optimal inbox placement. The agency often lifts deliverability above 95%, driving measurable boosts in engagement and sales for clients like Spotify and Airbnb.

Led by CEO Scott Cohen, InboxArmy’s 60+ team handles everything under one roof, strategy, design, development, automation, and compliance. Their Klaviyo Master Silver Partner status reflects deep proficiency across ESPs such as Salesforce, HubSpot, and Marketo.

And if consistency is the name of the game, InboxArmy plays to win. Clients report seamless migrations, increased sender reputation, and stronger ROI within the first quarter of collaboration.

Key Services

• Full deliverability audits, IP/domain warming, and reputation recovery
• ESP migration and platform evaluation for 50+ providers
• Advanced lifecycle automation and email flow setup
• Responsive template design and HTML coding
• SMS and multichannel automation integration
• Campaign management, reporting, and compliance oversight

2. Chronos Agency

Chronos Agency is a top pick, renowned for boosting profits for fast-growing DTC brands using Email, SMS, and Push Marketing. Their expertise and strategic marketing skills have led to revenue increases of 20% to 30% for ecommerce businesses.

With a global team of 80, they act as an extension of your own business, handling everything from copywriting and graphic design to strategy and execution.

Chronos Agency has generated over $181M in returns from email, impressing more than 300 clients with an average ROI of 3500%. They’ve collaborated with big names like The Oodie, Truly, Cise, and Forchics. With Chronos, it’s like having a top-tier marketing department without the hassle of office coffee runs or awkward water cooler chats.

Key Services

• They craft strategies to boost email open rates with engaging subject lines tailored to your audience.
• They streamline customer journeys, engaging your subscribers and boosting conversions.
• Chronos dives into your DTC store’s email marketing systems to identify and fix issues, creating a detailed action plan to accelerate your brand's growth.
• Their advanced customer behavior segmentation targets promotional emails, upsells, cross-sells, and engagement emails for maximum opens, clicks, and sales.
• Through continuous A/B testing, they ensure your emails deliver the highest possible ROI, tweaking everything from design to subject lines and send times to unlock hidden revenue for your store.

3. Aspekt

Working with brands like Mark Ingram and Urban Tots, one of the best standouts in this list is Aspekt, known for their expertise in both social media and email marketing, with Klaviyo as their trusty tool.

They understand that in today's digital world, an omnichannel approach is key, making sure all your marketing channels play nice together. Boasting an impressive track record, including over $10M in average revenue growth and 30M+ total emails sent, they prove that seeing the big picture leads to big results.

So, if you're looking to turn those Instagram likes into email opens and maybe a few cha-chas, Aspekt could be the perfect fit.

Key Services

• They have SMS marketing strategies that build priceless customer relationships, through customized SMS campaign management, so you never have to guess what to send next.
• Aspekt has SMS automation that ensure your subscribers get the right message at the right time!
• Always have your customer base in check with copy and designs that convert highly while staying true to your brand, with subscriber growth strategies to keep your SMS list growing around the clock.
• Continuous optimizations for high click and conversion rates and Constant monitoring and improvement of SMS deliverability to avoid any blacklist surprises.

4. The Email Marketers

Working with brands like Nerd, bud.com, and Cove, The Email Marketers offer a full suite of email marketing services specifically tailored to the Klaviyo platform. This includes everything from strategic campaign planning and eye-catching template design to compelling copywriting, advanced automation setup, in-depth segmentation, and ongoing performance analysis.

Their strength lies in providing end-to-end Klaviyo solutions designed to support ecommerce brands with diverse email marketing needs.

Key Services

• They develop email and SMS strategies that center around each customer’s unique journey. No more generic blasts; expect strategies as personalized as your grandma’s secret recipe.
• Your brand is one-of-a-kind, and so are their creative designs and copywriting. They focus on making your emails not just seen, but clicked, and converted.
• With a focus on spam prevention and deliverability, their email strategies are like the secret sauce to keep your messages in inboxes and out of junk folders.
• If you’re head over heels for email and want more, they optimize your on-site opt-ins and run list-growth campaigns that make your subscriber list grow faster than a viral cat video.
• Forget stressing about next week’s emails and SMS; they’ll map out your entire quarter with detailed campaign management and lifecycle automation, so you can focus on other things, like taking that well-deserved coffee break.

5. Arcady Media

When it comes to Klaviyo agencies, Arcady Media stands out with its impressive roster of over 300 satisfied clients, including well-known names like Hudson’s Bay, Ice Carats, PocketSpeech, and Tanoa. Arcady Media offers a complete email and SMS marketing solution tailored specifically for ecommerce businesses.

Their team of experts ensures that your campaigns are properly personalized, driving both sales and customer engagement. They deliver a full-service approach that replaces the need for multiple employees, all at a fraction of the cost. And who doesn’t love saving money without sacrificing quality?

Key Services

• Seamless migration from any platform to Klaviyo, complete with a comprehensive audit and action plan.
• They have a dedicated team of 6 experts ready to cater to every marketing need.
• Get In-depth competitor data analytics, covering frequency, terms, and send times, so your strategy is always a step ahead.
• With Arcady, get tailored retention strategies, including customer journeys and loyalty programs.
• Stay on top with creative implementation and detailed reporting.
• Robust email and SMS flows, monthly campaigns, and pop-up builds, all optimized for maximum impact.

6. DataSauce

When partnering with top brands like Godiva, Mister Zimi, Cygnett, and Daily Blooms, Data Sauce proves that retention marketing is more than just sending emails. It’s about crafting strategies that turn casual shoppers into loyal customers.

Imagine your CRM system becoming your brand's best friend, not just a digital address book. With expertise in everything from seasonal campaigns to data enrichment, Data Sauce makes sure your marketing efforts don’t just fill inboxes but actually drive results.

Key Services

• Data Sauce applies time-tested best practices to make sure every email and SMS is captivating and engaging, so your messages don't end up in the spam folder!
• If your emails are getting lost in spam, Data Sauce will audit your account and use proven strategies to get them back into the inbox. No more email ghosting.
• With extensive experience and deep technical know-how, Data Sauce can elevate your CRM strategy to new heights, ensuring your email campaigns are always on point.
• The creative team at Data Sauce breathes new life into your email designs, using data-driven insights to ensure your messages are fresh and effective.
• Data Sauce will streamline your marketing efficiency through smart automations, helping you generate passive revenue without blowing your ad budget.

7. Sticky Digital

If you’re seeking top-notch retention marketing, here’s why Sticky Digital deserves a spot on your radar. This agency specializes in making your customers stick around through email, SMS, loyalty programs, and tech stack optimization.

With a clientele that includes names like One Size, Nest Fragrances, and Uqora, and boasting an impressive 4200% ROI on email marketing, they truly know how to keep customers hooked.

Key Services

• Sticky Digital builds email and SMS programs that weave seamlessly into your tech stack, creating unforgettable and profitable user journeys.
• As Shopify experts, they craft tech stacks that don’t just look good; they work hard. They follow the “less is more” philosophy, creating streamlined and efficient tech stacks for Shopify that will make your wallet happy and your tech woes disappear.
• Whether it’s through subscription models, loyalty points, or exclusive perks, Sticky Digital’s strategies ensure your customers stay engaged. Their proprietary persuasion system has successfully scaled over 50 brands from modest figures to impressive revenues, proving that they’re the real deal.

When to Hire a Klaviyo Agency (And When to Keep It In-House)

It’s the age-old question for any business; when to hire an agency, when to keep the work in-house.

There’s no right answer for this. Every situation is different, and you can have success doing it either way.

You generally want to look at an agency if you’re struggling to get good results in-house, or it’s just something that your team never seems to have the time or bandwidth to own properly.

Here are some signs that’s the case, and you should look at contracting an agency:

• Email and SMS drive less than 20-25% of your revenue. For most ecommerce brands, owned channels should account for a meaningful slice of total sales. If you are well under that, there is likely revenue sitting in flows you have not built and segments you are not sending to.
• You only have a handful of basic flows running. A welcome series and an abandoned cart flow are the floor, not the ceiling. Post-purchase, win-back, browse abandonment, replenishment, and VIP flows are where a lot of automated revenue lives.
• Nobody owns the calendar. Campaigns go out when someone remembers, not on a plan. Frequency and consistency are most of the battle.
• Deliverability is slipping. Open rates are falling, or you are landing in the Promotions tab and spam folders. Fixing sender reputation is specialist work.
• You are migrating to Klaviyo from another platform and want the flows, templates, and data to come across cleanly.

Agency vs Freelancer vs In-House

Again - there’s no right or wrong answer. But there is a rough guide you can follow to find the best avenue for your brand, depending on what stage you’re at in your business:

• In-house makes sense once email and SMS are a large enough revenue line to justify a dedicated hire (or team). You get full control and deep brand context, but you carry the cost and the hiring risk.
• A freelancer or consultant is a fit for smaller brands that need the basics run, or for occasional strategy reviews. Lower cost, but usually one person covering strategy, design, and build.
• An agency gives you a team (strategist, designer, copywriter, technical specialist) and a process. It is the common choice for brands doing roughly $1M to $30M a year that want email and SMS run as a serious channel without building the function internally.

Looking to hire an agency for other areas of your business too? Check out our guides on picking the right Shopify Agency, or finding the best CRO Agency Partner.

How Much Does a Klaviyo Agency Cost?

Pricing varies widely, but there are clear patterns. Most Klaviyo agencies charge a monthly retainer somewhere between $2,000 and $15,000. A typical ecommerce brand doing $1M to $10M in annual revenue tends to land between $3,000 and $8,000 a month for a capable team. There are four common models:

• Flat monthly retainer ($2,000-$15,000/mo). The most common setup. A fixed fee covers flow setup, campaign strategy and sends, segmentation, and reporting within an agreed scope. Custom template design and SMS are often add-ons.
• Percentage of revenue (10-20% of attributed email/SMS revenue). Aligns the agency with your results, but gets expensive as you scale, and depends on attribution that Klaviyo credits generously. If you go this route, negotiate a cap.
• Project-based ($3,000-$25,000 per project). Good for a defined job: a full Klaviyo setup, a flow rebuild, a template system, or a migration. A fit for brands with an in-house team that needs expert help on specific work.
• Hourly consulting ($150-$400/hour). For occasional guidance rather than full management.

What You Get at Each Tier

• Budget ($1,000-$2,000/mo): a freelancer or junior team, a few campaigns a month, and basic flows. Fine for early-stage brands that just need the essentials running.
• Mid ($3,000-$5,000/mo): where most serious brands start. A real team, full flow architecture, custom design, regular A/B testing, and revenue-level reporting.
• Premium ($5,000-$10,000/mo): higher campaign volume, advanced segmentation and personalization, SMS strategy, and a dedicated senior strategist.
• Enterprise ($10,000+/mo): full retention marketing with a large team, multi-brand or international complexity, and custom attribution.

Costs to Budget For Separately

The agency fee is not the whole bill. Plan for the Klaviyo platform itself (from around $20/mo on small lists, rising past $1,000/mo at 100K+ contacts), SMS credits (roughly $0.01-$0.02 per text in the US), and any one-time onboarding or setup fee (commonly $1,000-$5,000). A good rule of thumb: the agency should pay for itself, with email and SMS driving a healthy 25-40% of total revenue once the program is running well.

Wrapping Up

Any of the agencies above can run a strong Klaviyo program. The right one for you comes down to fit. A brand fighting deliverability and scaling sends has different needs than one that wants a full retention system built from the ground up, and a $2M store and a $30M store are buying different levels of service. Match the agency's focus, team depth, and price to where your business actually is.

Whoever you pick, judge them on the same things: a real audit before they build, retention thinking that goes beyond campaign sends, deliverability they take seriously, and reporting that ties back to revenue rather than open rates.

Get those right and email and SMS can grow into a channel that drives a large share of your revenue while your team stays focused elsewhere.