Klaviyo is a marketing automation platform built for ecommerce, enabling brands to send behavior-based emails and SMS through deep integrations with Shopify, BigCommerce, and WooCommerce. For companies without in-house specialists, partnering with a Klaviyo-focused agency can significantly improve ROI through optimized flows, advanced segmentation, and performance-driven email strategies.
As a well known digital marketing strategist Amy Porterfield puts it, “Your email list is your business’s biggest asset. The more value you give, the more you get in return.”
This guide highlights the top 10 Klaviyo email marketing agencies known for turning passive subscribers into loyal buyers and building scalable, high-converting lifecycle systems.
What defines the best Klaviyo email marketing agency?
Our selection process began with a review of over 50 Klaviyo-specialist firms across global markets. We evaluated agencies based on five core criteria:
- Official Klaviyo partner status (Silver, Gold, or Elite)
- Documented ecommerce results (ROI, revenue attribution, retention growth)
- Automation sophistication (advanced flows, lifecycle design)
- Integration capabilities (SMS, conversion rate optimization, loyalty systems)
- Client satisfaction (verified reviews and retention metrics)
We prioritized agencies pushing Klaviyo’s capabilities forward, particularly those using predictive personalization, multi-channel automation, and first-party data enrichment. The top performers don’t just manage emails; they build complete customer lifecycle systems with a clear growth strategy behind every send.
Location: Grapevine, Texas, USA
Founded: 2016
Website: https://www.inboxarmy.com/
Markets Covered: Primarily US-based with international clients
CEO and Founder: Scott Cohen and Chris Donald
Example Clients: eBay, Spotify, Zappos, Cedar Electronics, Jockey, Airbnb, Expedia
LinkedIn: https://www.linkedin.com/company/inbox-army
G2 Reviews: 4.6 out of 5 stars based on 20+ reviews
There’s no way around it, the clear leader among the best Klaviyo email marketing agencies is InboxArmy. Headquartered in the U.S., InboxArmy is a top-tier email agency serving mid-sized businesses to enterprise clients across 25+ industries, including ecommerce, SaaS, universities, retail, real estate, food and beverage, banking, healthcare, automotive, pet care, travel, and manufacturing.
The agency checks all the boxes, merging a full-funnel strategy with advanced Klaviyo smart flows. Co-founded by email veteran Chris Donald and led by Scott Cohen, ANA’s Email Marketer of the Year, InboxArmy’s global team builds high-performance automations for brands like Airbnb and Spotify. Their Klaviyo implementations go far beyond flows, encompassing segmentation, deliverability optimization, and dynamic creative personalization.
As Cohen puts it, “Email marketing is a marathon, not a sprint.” That mindset underpins InboxArmy’s long-term approach to retention and revenue growth. With deep expertise across 40+ email service providers, they consistently position Klaviyo as the central engine of their clients’ CRM and UX ecosystems. Most importantly, they deliver measurable results, often generating 20–30% of total revenue directly through email. InboxArmy isn’t just a top contender, they’re the benchmark.
- Seven Marketing
Location: Manchester, United Kingdom
Founded: 2021 (4+ years)
Markets Covered: Primarily UK SMEs with both ecommerce and B2B clients
Example Clients: Not publicly listed; general SME portfolio
LinkedIn: https://www.linkedin.com/company/seven-marketing-agency
G2 Reviews: No dedicated G2 profile available
UK-based Seven Marketing specializes in using Klaviyo’s predictive analytics to drive conversions. Focused on ROI-first ecommerce email strategies, they layer personalized automations, making them a strong contender in our ranking. If you’re looking for an expert to take care of your cart recovery, browse abandonment and VIP flows, this is the right address. Their campaigns often see 4-8x ROI early on, making them a go-to for mid-market brands aiming to capitalize on their email list.
- Swanky
Location: Exeter, England, with additional offices in Australia and France
Founded: 2010
Markets Covered: Primarily ecommerce, especially Shopify Plus brands.
Example Clients: MyClothing, HelloFresh, Huel, Pasta Evangelists
LinkedIn: https://www.linkedin.com/company/swankyagency/
G2 Reviews: ~4.7/5
Swanky is a Klaviyo agency with a design-forward edge. These guys know their ways around visual storytelling, which is based on data-led strategy. Swanky can audit your Klaviyo account and ensure compliance as well as deliverability. You can trust them to build flows from welcome to win-back. Impressively, in one case they boosted deliverability by 622% in 90 days, restoring subscriber engagement and revenue.
- SmartSites
Location: Paramus, New Jersey, USA
Founded: 2011 (13+ years)
Markets Covered: Primarily North America, with global clients in UK, Australia, and Canada
Example Clients: Ancestral Supplements, Print Crazee, R & Y Compressors
LinkedIn: https://www.linkedin.com/company/smartsites
G2 Reviews: 4.8 out of 5 stars based on 230+ reviews
SmartSites views Klaviyo as a central growth engine, focusing on its ties with CRO, PPC and SEO. This firm is a certified and well-respected Klaviyo partner that caters to both tech startups and ecommerce brands. Their standout offering is robust calendar-driven automation and dynamic templates. Their clients typically see 5-9x ROI in the first year. SmartSites understands how to make Klaviyo something far bigger than just a messaging platform.
- BidPixel Marketing
Location: Southport, Queensland, Australia
Founded: 2017 (8+ years)
Markets Covered: Primarily Australia and Asia-Pacific; serves international ecommerce brands
Example Clients: Klaviyo partner directory list LinkedIn: https://www.linkedin.com/company/bid-pixel/ Klaviyo platform averages: 4.7/5 overall
BidPixel combines Klaviyo with targeted ads, which has proven to be a great strategy for multichannel growth. They are certified Klaviyo partners who have mastered the way around your customer’s psyche. If you want to build behavior-triggered flows or you’re interested in dynamic audience syncs, this agency knows it all. Their case study showed Klaviyo accounting for 41% of total revenue in week one, while merging automated flows with weekly campaigns.
- Enflow Digital
Location: Vilnius, Lithuania
Founded: ~2019 (6+ years in email marketing)
Markets Covered: Global ecommerce brands (50+ clients)
Example Clients: Alkaline Herb Shop, SensAsia Spas, Vetz Petz, Overnight Glasses
LinkedIn: https://www.linkedin.com/company/enflowdigital/
Klaviyo’s platform averages: 4.7/5
An international Klaviyo agency partner that specializes in predictive email frameworks for both DTC and enterprise brands. If there’s something they can boast about it’s definitely years of platform expertise and consistent earnings of top-tier ratings on every review site. Enflow builds advanced segmentation and AI-enhanced triggers, gaining some major points in our ranking for advancement. Their clients benefit from consistent lifts in conversion rates, importantly customer lifetime value is told to rise by 20–40%. Their responsive UX design works perfectly with Klaviyo.
- Mr Digital
Location: Brighton, East Sussex, UK
Founded: ~2016 (8–9 years)
Markets Covered: UK-based with a focus on small-to-medium businesses Example Clients: Orion Safety Belts, HS Wood Flooring, The Berkeley Hotel LinkedIn: https://www.linkedin.com/company/mr-digital-limited/
G2 Reviews: No dedicated G2 listing
Mr Digital, serves UK/AU markets, but was noticed on our radar specifically for their complex client-focused approach. Their team of copywriters, designers and analysts really takes on each case individually, according to the reviews. A very interesting service is the integration of Klaviyo email with CRO and web development. Brands who cooperate with them see email revenue growth, but most importantly an increased on-site conversions thanks to better UX alignment.
- Polaris Growth
Location: The Hague & Amsterdam, Netherlands (HQ)
Founded: 2012 (13+ years), began Klaviyo in 2016
Markets Covered: Benelux & EU-focused with international ecommerce clients
Example Clients: Soft Revolt, Meesterslijpers, RiZZ, GrubTerra
LinkedIn: https://www.linkedin.com/company/polaris-growth/
G2 Reviews: No agency-specific profile; Klaviyo platform averages about 4.7/5 overall
Polaris Growth offers a structured Klaviyo strategy tailored for product-led DTC brands. They begin with brand immersion, build modular master templates and create core flows (welcome, abandoned, win-back). You can trust their process which involves A/B testing flows monthly and refining based on heat-map and click metrics.
9.WebGas
Location: Benevento, Italy
Founded: 2019 (6+ years)
Markets Covered: Primarily Italy and wider EU; supports Shopify/Klaviyo ecommerce brands Example Clients: Decidiprezzo, Fusco Boutique, Bata (based on client testimonials) LinkedIn: https://www.linkedin.com/company/19232042/
G2 Reviews: No dedicated G2 profile; platform reviews not available
Based in Europe, WebGas is a certified Klaviyo partner known for financial metrics-driven flows. They set up high-impact automations and tie Klaviyo to Shopify, CRO as well as analytics stack. WebGas earned their spot in our ranking thanks to their service of ongoing training to keep clients ahead while syncing Klaviyo with paid campaigns. No need to have much experience to feel properly taken care of!
- Magnet Monster
Location: London, England, UK
Founded: 2018 (6+ years)
Markets Covered: Primarily DTC and ecommerce brands in the UK, EU, and Australia Example Clients: Little Big Playroom, Spotlight Oral Care, Sleep Easy, BodyBuilding LinkedIn: https://www.linkedin.com/company/magnetmonster/
G2 Reviews: No dedicated G2 profile; Klaviyo platform averaging ~4.7/5
Monster and angel, this agency focuses on Klaviyo acquisition and onboarding funnels that turn anonymous visitors into high-performing email sequences. Magnet Monster closes our ranking of best Klaviyo email marketing agencies with their eye-catching “Smart Flow Builder”, which captures data to dynamically swap imagery and recommendations. Clients can expect 40-60% higher open rates. For brands focused on list-building and early marketing momentum, Magnet Monster delivers Klaviyo gains fast.
Summary
In 2025, the best Klaviyo email marketing agencies distinguish themselves through advanced personalization, a client-first mindset, and a strong balance of creativity and technical innovation. InboxArmy continues to set the standard for global, data-driven Klaviyo execution, particularly in complex lifecycle deployments. Agencies like Seven Marketing and Swanky also earn top recognition for their use of predictive analytics and automation precision.
When choosing a partner, focus on the specific areas where your brand needs the most support, whether that’s segmentation, deliverability, or campaign strategy. The most effective agencies combine creative insight, technical fluency, and strategic direction to unlock Klaviyo’s
full potential. And if you’re still underestimating the power of this platform, now’s the time to wake up, your inbox can become one of your most scalable revenue channels.
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