FJ Solutions
10 Best Email Marketing Agencies in the USA (2026)
10 min read
Table of contents
Finding a good email marketing agency in the USA is harder than it looks.
There are hundreds of options, but most are either too generic, too expensive, or not built for ecommerce.
This list focuses on agencies that actually specialize in ecommerce email, have a track record with real brands, and know how to drive revenue, not just open rates.
We evaluated each agency across five areas: ecommerce focus, Klaviyo capabilities, services offered, team quality, and results.
1. FJ Solutions
Website: fjsolutions.com
Location: Miami Beach, FL (teams in Argentina and Spain)
Founded: 2004
Klaviyo Partner: Yes
Best for: Ecommerce brands on Shopify that want a dedicated, results-focused email and SMS team
FJ Solutions is a full-service ecommerce agency with over 20 years of experience. Their email and SMS division runs exclusively on Klaviyo, and every account is staffed with a dedicated senior team, not junior generalists.
They combine automation strategy, advanced segmentation, and continuous A/B testing to build programs that generate real revenue from the list.
What they offer:
- Klaviyo audits and account setup
- Email and SMS strategy
- Customer journey automation (welcome, abandoned cart, post-purchase, win-back)
- Campaign management
- Advanced segmentation and A/B testing
- Lead generation and signup form optimization
- Database cleaning and deliverability maintenance
- Email and SMS design and copywriting
- Klaviyo review integration
2. Flowium
Website: flowium.com
Location: New York, NY
Founded: 2017
Klaviyo Partner: Yes
Best for: DTC brands that need a Klaviyo specialist to build and manage lifecycle flows
Flowium focuses almost entirely on Klaviyo-powered ecommerce lifecycle marketing. They work with brands in fashion, beauty, wellness, and consumer goods, building welcome sequences, cart flows, post-purchase programs, and win-back campaigns. A solid option if your priority is Klaviyo depth over broad service coverage. Pricing starts around $2,000/month.
What they offer:
- Klaviyo flow strategy and build
- Campaign management
- Segmentation and list management
- Email copywriting and design
- Performance reporting
3. Enflow Digital
Website: enflowdigital.com
Location: USA (remote)
Founded: 2022
Klaviyo Partner: Yes
Best for: Brands that need a full audit and rebuild of their email and SMS program
Enflow takes an audit-first approach. Before touching anything, they analyze the full ESP setup, deliverability health, and automation gaps. From there they rebuild flows, run structured A/B tests, and manage ongoing campaigns. A good fit for brands that have grown fast and need to professionalize their retention marketing.
What they offer:
- Email and SMS audits
- Flow rebuilds and optimization
- A/B testing
- Campaign management
- Deliverability monitoring
4. Sweatpants Agency
Website: sweatpantsagency.com
Location: Los Angeles, CA
Klaviyo Partner: Yes
Best for: Fashion, beauty, and lifestyle DTC brands that want strong creative direction alongside Klaviyo strategy
Sweatpants Agency is a boutique agency based in LA that combines Klaviyo strategy with in-house creative. Clients in fashion and lifestyle get campaigns that feel like editorial content rather than promotional email, with technically sound flows built on the same team that handles design and brand voice. Pricing starts around $2,500/month.
What they offer:
- Klaviyo strategy and flow architecture
- In-house email design and creative direction
- Campaign management
- Segmentation and A/B testing
- Performance reporting
5. Retention Commerce
Website: retentioncommerce.com
Location: Los Angeles, CA
Klaviyo Partner: No
Best for: Ecommerce brands on Shopify that want lifecycle automation built around actual customer behavior, not scheduled sends
Retention Commerce is a boutique agency focused entirely on Shopify brands. Their approach centers on behavioral automation: flows triggered by what customers actually do on your site rather than a fixed calendar. A practical fit for brands that have had inconsistent agency experiences and want a defined, milestone-based optimization process with clear deliverables at each stage.
What they offer:
- Behavioral lifecycle automation
- Flow strategy and build
- Segmentation and audience management
- Campaign management
- A/B testing
- Performance reporting
6. Rejoiner
Website: rejoiner.com
Location: New York, NY
Klaviyo Partner: No
Best for: High-volume ecommerce businesses focused on cart recovery and lifecycle automation.
Rejoiner combines proprietary software with a full-service email team. They focus heavily on abandoned cart recovery and lifecycle campaigns, and clients have reported up to 30% increases in email revenue. A good fit for brands with complex data needs or higher email volumes.
What they offer:
- Abandoned cart and browse abandonment flows
- Lifecycle campaign strategy
- Personalized dynamic content
- Predictive analytics integration
- Full campaign management
7. SmartMail
Website: smartmail.io
Location: USA
Klaviyo Partner: No
Best for: DTC brands looking for trigger-based email campaigns powered by behavioral data
SmartMail has sent and tested over 11 billion emails, which gives them a lot of real-world data to draw from. They specialize in trigger-based campaigns: cart recovery, browse abandonment, and post-purchase sequences built around what users are actually doing on your site.
What they offer:
- Trigger-based email automation
- Cart and browse abandonment flows
- Post-purchase sequences
- Predictive personalization
- A/B testing at scale
8. One 10 Media
Website: one10media.com
Location: USA
Klaviyo Partner: No
Best for: DTC brands in fashion, beauty, and wellness that want email and SMS working as one program
One 10 Media is a small retention agency that integrates email and SMS into a single customer journey. They work across fashion, beauty, health, supplements, and food, and tend to operate as a close extension of the brand’s internal team rather than a traditional outside agency.
What they offer:
- Email and SMS strategy
- Lifecycle flow design
- Campaign management
- Audience segmentation
- Retention and repeat purchase optimization
9. Hustler Marketing
Website: hustlermarketing.com
Location: USA
Klaviyo Partner: Yes
Best for: Shopify brands that want a results-focused team willing to test aggressively
Hustler Marketing builds and manages Klaviyo programs for Shopify brands with a clear focus on revenue, not vanity metrics. They move fast, test a lot, and are a good match for brands that want an agency that acts less like a vendor and more like a growth partner.
What they offer:
- Klaviyo flow setup and management
- Campaign strategy and execution
- Segmentation
- A/B testing
- Revenue-focused reporting
10. Dido Agency
Website: didoagency.com
Location: USA
Klaviyo Partner: No
Best for: Early-stage ecommerce brands building their email program from the ground up
Dido Agency covers the essentials well: campaign management, automation setup, template design, and performance analysis. The most accessible option on this list, and a reasonable starting point for brands that don’t yet need advanced segmentation or multi-channel lifecycle strategy.
What they offer:
- Email campaign management
- Automation setup
- Template design
- List management
- Performance reporting
How to Pick the Right Agency for Your Brand
If you’re on Shopify and using Klaviyo, prioritize certified Klaviyo Partners. FJ Solutions, Flowium, Sweatpants Agency, and Hustler Marketing are the strongest options here.
If you want senior access, boutique agencies like FJ Solutions, Retention Commerce, and Sweatpants Agency keep accounts staffed with experienced people. Larger shops often hand off to junior staff once you’re onboarded.
If you need more than email, FJ Solutions is the only agency on this list that covers email, SMS, SEO, paid ads, and development under one roof.
If you’re early stage, Dido Agency or Enflow Digital are more accessible entry points.
On budget, most agencies here start between $1,500 and $3,000/month. FJ Solutions has tiered plans that let you start lean and scale.
Frequently Asked Questions
They handle everything your email program needs: strategy, design, copywriting, automation setup, segmentation, campaign management, A/B testing, and reporting. For ecommerce specifically, this includes building automated flows like welcome series, abandoned cart, post-purchase, and win-back sequences.
Most retainers run between $1,000 and $5,000 per month depending on scope and service level. Agencies like FJ Solutions offer tiered plans so you can start at a lower level and grow as your program develops.
Klaviyo is the leading email and SMS platform for ecommerce. It integrates directly with Shopify and WooCommerce, allowing agencies to build behavioral automations, real-time segmentation, and revenue attribution that generic email tools can’t match. Working with a certified Klaviyo Partner means your team has been trained and vetted by Klaviyo directly.
Most brands see measurable results within 60 to 90 days of launching a full program. Cart abandonment and welcome flows typically show impact first, followed by post-purchase and win-back sequences as the list grows.
Campaigns are one-time sends: promotions, newsletters, product launches. Flows are automated sequences triggered by user behavior, like a new subscriber, an abandoned cart, or a completed purchase. A solid email program runs both in parallel.
Yes. Email consistently returns $36 to $42 per dollar spent when managed properly. With paid acquisition costs still rising, email remains one of the most cost-efficient channels to drive repeat purchases and grow customer lifetime value.
Last updated: May 2026
