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TL;DR: A Klaviyo agency for Shopify brands builds and manages your email and SMS so it drives real revenue, not just sends. Good ones run audits, build flows, manage campaigns, and protect deliverability. The best brands target 30% or more of revenue from email. This guide shows what agencies do, how to choose one, what to pay, and the red flags that signal you're about to waste money.
Hiring a Klaviyo agency for Shopify brands is one of the fastest ways to turn a neglected email list into a real revenue channel. Most Shopify stores leave money on the table because their flows are half-built and their campaigns go to everyone at once. A strong agency fixes that. Email should drive a large share of your store's revenue, and when it doesn't, the problem is usually strategy and execution, not the platform. This guide breaks down what a Klaviyo agency does, when to hire one, how to vet them, and what fair pricing looks like in 2026.
What is a Klaviyo agency?
A Klaviyo agency is a team that runs your email and SMS marketing inside Klaviyo on your behalf. They handle strategy, copywriting, design, automation, and reporting so you don't have to. Think of it as an outsourced email department built for Shopify.
Most agencies specialize because Klaviyo rewards depth. The platform connects to your Shopify data, tracks every customer action, and lets you trigger messages off real behavior. Knowing how to use segments, flows, and predictive data well is a skill that takes years to build. A good Klaviyo agency for Shopify brands brings that skill on day one, plus a clear view of what strong performance looks like across many stores at your stage of growth. Across the Shopify stores we manage at CartStrings, we typically see email drive 32% of total revenue once the core flows and segmentation are dialed in.
When to hire an agency?
Hire a Klaviyo agency when email is clearly underperforming and you don't have the time or in-house skill to fix it. The clearest signal is revenue. If email drives less than 20% of your total, you're leaving money behind.
Klaviyo's own benchmark data shows email programs should drive roughly 30% to 40% of total revenue for optimized ecommerce brands, with about 33% being typical for stores that have their automations and segmentation in place. Most Shopify brands sit well below that. If your flows are incomplete, your open rates are sliding, or your campaigns all go to your full list, those are signs you need help. Brands doing $500k or more a year usually reach the point where a specialist pays for itself fast. You can start with a Klaviyo audit to see the size of the gap before committing to a full engagement.
What agencies actually do
A Klaviyo agency runs four core jobs: it audits your account, builds your automated flows, manages your campaign calendar, and protects your deliverability. Each one maps to a specific lever on revenue.
The foundation is always the automated flows. Klaviyo's benchmark report found that flows generate close to 41% of all email revenue from just 5.3% of total sends, with revenue per recipient roughly 18 times higher than one-off campaigns. That is why agencies build out the email automations first: welcome, abandoned cart, browse abandonment, post-purchase, and winback. The abandoned cart flow alone averages about $3.65 in revenue per recipient, and the top 10% of brands pull nearly $29 per recipient, according to Klaviyo's abandoned cart benchmarks.
On top of the flows, an agency runs your email campaigns, the regular sends tied to launches, promotions, and content. They use segmentation so the right message reaches the right people instead of blasting everyone. Welcome emails alone average about $2.65 per recipient in Klaviyo's benchmark data, and the top 10% of brands pull more than $21 per recipient, so the gap between average and elite execution is huge. That gap is exactly what a good agency closes. And they manage deliverability, the technical work that keeps your emails in the inbox instead of spam. Without that last piece, none of the rest matters, because an email that lands in spam earns nothing no matter how good the copy is.
How to choose an agency
Choose a Klaviyo agency by judging its process, its proof, and its people. The best agency is the one that can show you a clear method, real client results, and account managers who aren't stretched thin. Ask hard questions before you sign anything.
Start with strategy. Ask how they approach segmentation, what flows they build first, and how they think about your specific category. Then ask about execution: their campaign workflow, their A/B testing framework, and their deliverability practices. Move to results: which metrics they track, whether they can show case studies with real revenue numbers, and what timeline they consider realistic. Finally, ask about the team. The number of clients per account manager matters more than people expect. Two to five clients per manager is a healthy load. If one person juggles ten or more accounts, your store will get template work and slow replies. If you can, talk to a current client and ask whether they'd hire the agency again.
Red flags to watch for
The biggest red flag is an agency that guarantees a specific revenue number. No honest agency can promise exact results, because outcomes depend on your products, margins, list, and offer. A guarantee is a sales tactic, not a forecast.
Watch for a few other warning signs. An agency that only talks about open and click rates is selling vanity metrics, not revenue. One that can't explain its process simply probably doesn't have one. Cookie-cutter templates instead of custom strategy mean you're getting a factory, not a partner. Hidden pricing, overloaded account managers, and no real deliverability expertise all point the same direction. And if most of their clients leave within a few months, that churn usually signals weak results or poor communication. A good sign worth looking for: an agency that asks more questions about your goals and data than it spends pitching.
Agency pricing explained
Most Klaviyo agencies charge a monthly retainer between $3,000 and $12,000, depending on scope, send volume, and whether SMS is included. That fee is separate from what you pay Klaviyo for the platform itself.
It helps to understand both costs. Klaviyo bills based on active profiles, anyone you've messaged in the last 30 days, not on emails sent. Pricing starts around $20 a month for small lists and scales to roughly $150 a month at 10,000 profiles and about $720 a month at 50,000 profiles, with SMS adding more on top. Klaviyo's pricing documentation lays out the full tiers. When you evaluate an agency retainer against the platform cost, the math is straightforward: if email should drive 30% of revenue and an agency moves you from 15% to 30% on a store doing $500k a year, that's a large return relative to the fee. Ask any agency to walk you through that revenue model for your numbers, not generic ones.
Agency vs in-house
Choose an agency when you need senior expertise fast and don't have it on staff. Build in-house when email is mature enough to run on documented systems and you want full daily control. Many growing Shopify brands use an agency to build the engine, then hire internally to maintain it.
The real comparison is total cost and speed. A capable in-house email marketer commands a full salary plus benefits, and you still need design and copy support around them. An agency brings a full team, a tested process, and pattern recognition from dozens of stores for a predictable monthly fee. For most brands under $5 million a year, an agency reaches strong performance faster and cheaper than building a team from scratch. The strongest move is often a hybrid: let a specialist establish your flows, segmentation, and deliverability, then decide what to bring in-house once the system is proven. If you want to see what that engine looks like for your store, you can book a call or browse more guides in our articles library.
Conclusion
A Klaviyo agency for Shopify brands earns its fee by turning email from an afterthought into a channel that reliably drives 30% or more of revenue. The work is concrete: audit the account, build the flows that produce most of the revenue, run smart campaigns, and protect the inbox. The hard part is picking the right partner. Judge agencies on process, proof, and team load, not on promises. Avoid anyone selling guaranteed numbers or hiding behind vanity metrics. Weigh the retainer against the revenue it can realistically unlock for your specific store, and consider a hybrid path as you scale. If your email isn't pulling its weight, the gap is almost always fixable, and it's usually bigger than you think. Start with an audit and build from there.
Frequently Asked Questions
What does a Klaviyo agency do?
A Klaviyo agency manages your email and SMS marketing inside Klaviyo. That includes auditing your account, building automated flows like welcome and abandoned cart, running your campaign calendar, segmenting your list, and protecting deliverability. The goal is to grow the share of revenue email drives for your Shopify store.
What does an agency cost?
Most Klaviyo agencies charge a monthly retainer of roughly $3,000 to $12,000, based on scope and send volume. That is separate from Klaviyo's platform fee, which scales with your active profile count. Evaluate the retainer against the revenue email can realistically add, not as a flat expense.
Is an agency worth it?
For most Shopify brands doing $500k or more a year, yes. Email should drive about 30% to 40% of revenue, and most stores sit well below that. A specialist closes that gap faster and cheaper than building an in-house team from scratch, especially for the high-value automated flows.
How do I choose one?
Judge an agency on its process, its proof, and its people. Ask how they handle segmentation, flows, testing, and deliverability. Request case studies with real revenue numbers. Check how many clients each account manager handles; two to five is healthy. Talk to a current client if you can.
Agency or in-house?
Hire an agency when you need senior expertise fast and lack it on staff. Build in-house when email is mature and runs on documented systems. Many growing brands use a hybrid: an agency builds the flows, segmentation, and deliverability, then they bring maintenance in-house once the system is proven.
