Email and SMS flows are the most effective revenue channels most Shopify brands still underinvest in, and the agency you hire determines whether you get a genuine lifecycle system or a rehashed welcome series. The evidence is hard to dispute: in an analysis of 24 billion emails, 230 million SMS messages, and 413 million push notifications sent by merchants in 2024, automated emails generated 37% of sales from just 2% of email volume, while automated SMS generated 18% of orders from 9% of sends, according to Omnisend's 2025 ecommerce marketing report. Triggered messages also convert clickers far better than scheduled ones.

The seven picks below are profiled the way you'd hire: partner tier, engagement model (retainer, project, or one-time payment), channel scope, the brand size each one fits, and whether pricing is published or quoted. Start with a Klaviyo agency that builds for revenue, then read the rest to compare.

Table of Contents

• 1. Class A Media
  • The engagement model
• 2. Chronos Agency
  • Where Chronos fits
• 3. Flowium
• 4. Fuel Made
• 5. Underground Ecom
  • The brand-size spread
• 6. Structured Agency
  • When team scale helps
• 7. RYO Agency
• Klaviyo Agency Partners at a Glance
• How to Choose Your Klaviyo Partner and Next Steps

1. Class A Media

Class A Media is an official Klaviyo Partner named one of Klaviyo's fastest-growing agencies. Its work focuses exclusively on Klaviyo email and SMS flows, making it a fit for ecommerce brands that want to build retention around customer behavior and repeat purchases rather than add another marketing channel.

The agency's scope extends beyond welcome and abandoned-cart messages. Its Flow Blueprint combines lifecycle strategy, copywriting, design and Klaviyo buildout, with behavior-based triggers and customer journey mapping. Class A Media reports that the system has driven $150M+ in revenue for 200+ ecommerce brands.

The engagement model

Class A Media describes its commercial model as a one-time payment rather than an ongoing retainer. Pricing is quoted after a consultation, where the team can develop a specific plan. That structure can suit brands that want a custom flow system without a recurring agency fee. The trade-off is that a one-time build does not replace the need for someone to manage campaigns and retention work after launch.

Pros

• One-time project model: avoids an ongoing agency retainer.
• Flow-focused scope: strategy, copywriting, design and Klaviyo implementation are built around customer lifecycle communications.
• Established track record: the Flow Blueprint is described as the system behind $150M+ in revenue for 200+ ecommerce brands.
• Klaviyo credentials: Class A Media is an official Klaviyo Partner and is named one of Klaviyo's fastest-growing agencies.

Cons

• Pricing is quoted: brands need a consultation to receive a custom plan.
• Klaviyo-specific delivery: businesses must use Klaviyo, or be open to migrating to it, for Flow Essentials.

Website: Class A Media

2. Chronos Agency

Chronos Agency holds Elite Master status and runs lifecycle programs across email, SMS, RCS, push and direct mail. The channel list is the tell. A shop with a working email program that wants SMS and push to behave as one system has somewhere to go here. A store still fixing its welcome flow is paying for reach it won't use.

Tier labels mean less than buyers assume, but they aren't meaningless. Klaviyo has been publicly segmenting agency partners by strategy, service quality and experience since at least September 2023, when it named nine new Elite Master Partners including Northern, Mineral.io, Hustler Marketing, Noticed, AMB Interactive, Elephant Room, Mailody, Code and Ackerman, according to Klaviyo's partner awards announcement. The badge signals a managed-account track record, not a guarantee of fit.

Where Chronos fits

Chronos reports work with more than 500 brands, including The Oodie, Organifi and Fenix, and its positioning skews toward scaling accounts with meaningful revenue. Coverage runs from flow architecture and campaign planning to copy, design, segmentation, deliverability, testing, migrations and onboarding.

Pros

• Elite Master tier: the highest agency tier in Klaviyo's ecosystem, with the product access that comes with it.
• Multi-channel reach: email, SMS, RCS, push and direct mail under one team.
• Published proof: named client examples plus a free strategy call and lifecycle audit as an entry point.

Cons

• Size floor: the focus on scaling brands makes very small stores a poor economic fit.
• Quote-based pricing: minimum engagement requirements aren't specified anywhere public.

If you're mapping tiers before you shortlist, this breakdown of Klaviyo partner tiers saves an afternoon of tab-hopping.

Website: Chronos Agency

3. Flowium

A useful economics check: Klaviyo reports that partners generate at least $3 in implementation, strategy and managed-services revenue for every $1 of Klaviyo monthly recurring revenue, per Klaviyo's partner program page. Full-service shops price against that services layer, not against your software bill.

Flowium is a full-service lifecycle shop at the Elite Master tier, covering account setup, automated flows, campaigns, copy, design, technical maintenance, testing and optimization. It also runs SMS, WhatsApp, RCS, Instagram DM automation, push and direct mail, which makes it a genuine one-vendor option for brands consolidating a scattered retention stack. Client examples include True Classic, Dr. Squatch, RSVLTS and Last Crumb.

The commercial detail worth knowing: Flowium's FAQ describes month-to-month agreements, which lowers commitment risk, but it also describes a 60-day cancellation notice. Get both terms in writing before signing, because a month-to-month label with a two-month exit isn't the flexibility most buyers picture.

Pros

• Broad retention services: flows, campaigns, deliverability, design and extra channels in one place.
• Published case studies: enough material to judge vertical fit before a call.
• Month-to-month option: per its FAQ, useful if you're testing an agency relationship.

Cons

• Quote-based pricing: no fixed packages published.
• Exit terms matter: confirm the cancellation window, not just the contract label.
• Scope may overshoot: a brand wanting a one-time flow build is paying for services it won't use.

Website: Flowium

4. Fuel Made

Fuel Made is a strong fit when Shopify infrastructure is part of the retention problem. The Elite Master partner combines Shopify and Shopify Plus experience with retention services, including strategy, creative, implementation, optimization, lifecycle automation, segmentation, deliverability, testing and reporting.

Check how the agency plans to use benchmarks in its reporting. Klaviyo provides peer benchmarks only to accounts with at least 25 delivered emails in the previous six months. SMS benchmarks have a separate threshold of 25 delivered messages, assessed independently by channel, according to Klaviyo's benchmark eligibility documentation. If your account has limited sending volume, ask whether it qualifies before treating peer comparisons as a performance target.

Fuel Made offers both retainer and project-based engagements. It generally works with established DTC brands that have meaningful annual revenue, so smaller stores should clarify whether their budget and account scope fit before committing.

Pros

• Shopify depth: A practical choice when theme, data layer or platform issues affect retention performance.
• Project-based work: An option for brands that do not want an ongoing retainer.
• Experience across categories: Its listed verticals include apparel, beauty, supplements, pet, home and sporting goods.

Cons

• May not suit early-stage stores: Established-brand experience can mean a mismatch if your account needs are still small.
• Check vertical fit: Ask for relevant case studies rather than relying on broad category coverage.
• No published prices: Expect to discuss scope and budget directly.

For a broader comparison of agency service models, see this guide to email marketing agencies.

Website: Fuel Made

5. Underground Ecom

The selection question has shifted. Klaviyo's March 2025 K:Partners expansion added an AI assistant, CRM enablement, partner discovery and a technology-partner track, and its partner materials describe more than 6,500 agency partners and over 350 integration partners, with 85% of Klaviyo customers enabling at least one integration, per Klaviyo's K:Partners announcement. Once predictive triggers and multi-system data flows sit inside the account, integration hygiene matters as much as creative quality.

Underground Ecom fits that environment as an Elite Master partner running end-to-end Klaviyo account management: strategy, content, segmentation, testing, technical support and reporting. It takes project-based and retainer work and reports serving brands from under $1M to more than $500M in annual revenue, with listed examples including AG1, Virgin, Kiko Milano and Huda Beauty. A free audit is listed in its partner profile.

The brand-size spread

That range cuts both ways. A brand at $2M gets access to a team used to enterprise complexity, which is good discipline on data structure and consent management. It also means your account can sit below the agency's most experienced staff unless you ask who runs the day-to-day work.

Pros

• Elite Master tier: strong technical bench and product access.
• Wide size range: relevant from sub-$1M brands to enterprise portfolios.
• CRM-team model: works well when you have in-house marketers who want a partner inside the account rather than a black box.

Cons

• One-time builds need scoping: clarify the team's role and deliverables if you only want flows built.
• Self-reported credentials: test awards and performance claims against case studies close to your category.
• No published pricing: standard rates aren't listed.

Website: Underground Ecom

6. Structured Agency

Klaviyo partner tier can help you check an agency's credentials, but it won't tell you whether its engagement model fits your needs. Klaviyo's partner program requirements list managed-revenue thresholds of $250 for Silver, $5,000 for Gold and $20,000 for Platinum, plus minimum certification counts for each tier, as outlined in Klaviyo Academy's partner program requirements. Ask Structured which tier it holds, who would manage your account and whether the work is project-based or ongoing.

Structured focuses on ecommerce email and SMS and supports Shopify and Shopify Plus. Its profile presents a broad client roster, but logos alone won't show whether the agency understands your catalog, price point or repeat-purchase cycle. Review the public portfolio and ask for examples that match your business model.

When team scale helps

Structured may suit brands with frequent launches, seasonal campaigns or a steady need for creative production. More production capacity can help keep a busy calendar on track. For a single welcome-flow rebuild or a few post-purchase sequences, a tightly scoped project may be a better fit than an ongoing agency relationship.

Pros

• Platinum Master status: a verifiable tier with published requirements.
• Public portfolio: review the creative work before making contact.
• Production capacity: relevant for brands with frequent campaign needs.

Cons

• Limited public detail: confirm the engagement structure and who will handle delivery.
• Pricing not listed: request a scoped proposal before budgeting.
• May exceed a narrow project's needs: define deliverables before committing to ongoing support.

Before a scope call, use this guide to choosing an e-commerce marketing agency to prepare questions about fit, ownership and deliverables.

Website: Structured Agency

7. RYO Agency

SMS is where enthusiastic agencies get brands into trouble. Klaviyo's US guidance for SMS abandoned-cart flows sets hard mechanics: enable double opt-in, send no more than one SMS per recipient in the flow, deliver the message within 48 hours of the triggering event, obtain express consent for SMS and cart-abandonment messages, and include the required disclosures in your mobile terms of service and privacy policy, per Klaviyo's SMS cart-abandonment help article. Consent status, frequency and timing are the product, not the cart data.

RYO Agency is a Platinum Master partner running email and SMS retention programs that cover account setup and cleanup, segmentation, campaign planning, flows, list growth, popup optimization, testing and revenue reporting. It advertises a free audit for qualified ecommerce brands, complimentary migration to Klaviyo and a strategy session.

That combination suits a brand with a messy account: the cleanup and popup work fixes the inputs that feed every flow downstream. It's also a recurring-campaign model by design, with monthly reporting built in.

Pros

• Platinum Master status: a checkable tier with published requirements behind it.
• Inputs and automation together: list growth and popup optimization sit alongside flows.
• Low-risk entry: a free audit and strategy session let you see the account diagnosis first.

Cons

• Limited public detail: team size, vertical specialization and case studies are thin.
• Recurring orientation: confirm whether one-time project work is available at all.
• No published pricing: expect a quote after the audit.

If you want to widen the field beyond Klaviyo-only shops, these agency support solutions are worth a scan before you commit.

Website: RYO Agency

Klaviyo Agency Partners at a Glance

How to Choose Your Klaviyo Partner and Next Steps

Match agency scale to brand stage first, because everything else follows from it. A store under $1M in annual revenue needs clean event tracking and flow architecture, not an 80-person team running weekly campaigns. A brand between $10M and $50M usually needs campaign production capacity, deliverability management and someone who can hold a Shopify Plus migration together. Paying enterprise rates for a build your team will own anyway is the most common waste in this category.

Decide the engagement model before you take a single call. A retainer buys ongoing execution and someone accountable for the channel month to month. Project work buys a defined build with a finish line. A one-time payment buys the system itself, with your team operating it afterward. Each is correct for a different operating reality, and no agency can price until it knows which one you want.

Then verify. Ask for two case studies in your vertical with the actual flow logic, not just the percentage lift. Klaviyo reported more than 193,000 customers worldwide at the end of 2025, up from more than 167,000 at the end of 2024, and names expanding agency partnerships among its inbound channels, according to Klaviyo's fiscal 2025 annual report. More merchants and more partners means more choice, and more reason to test claims against your own numbers rather than a sales deck.

Action checklist: request an audit or a tailored plan, confirm you get access to and ownership of the flow logic inside your own Klaviyo account, ask for contract length and cancellation notice in writing, and get the post-launch scope documented before anyone touches a trigger.

Benchmarking helps here, and the same method applies when choosing a competitor review for merchants to compare shortlisted agencies side by side on tier, model and fit. Klaviyo agency partners are not interchangeable, and the badge tells you less than the engagement model does. Start with a Klaviyo agency that will show you the flows, the logic and the reporting before you sign. The right partner is the one whose engagement model matches how you want to own your retention infrastructure.

Class A Media builds Klaviyo email and SMS flow systems for Shopify brands on a one-time project payment, with no ongoing agency retainer, and reports more than $150M in attributable flow revenue across 200+ brands and 100+ niches. If your welcome and cart flows are doing all the work in your account, the team can scope a custom lifecycle build around your catalog, your customer behavior and the revenue you're already leaving on the table. Visit Class A Media to request a custom plan and see what a full flow system would look like for your store.