Every agency here is a Klaviyo partner that runs email, SMS and the channels around them for Shopify brands in the US, the UK or both. The right one depends on your size and how your customers buy, so each entry says who it suits.
The shortlist at a glance
| Agency | Good fit for | Klaviyo listing | Based |
|---|---|---|---|
| Email Kong | Subscription and repeat-purchase Shopify brands | Master Platinum | London |
| Underground Ecom | Larger US and UK brands that want retention plus acquisition | Master Elite | US and UK |
| Chronos Agency | Brands of $10M+ that want email, SMS and direct mail | Master Elite | Singapore and Sydney |
| Structured | Established DTC brands that want email and SMS | Platinum Master | Not stated |
| Fuel Made | Shopify brands of $10M-$100M that also want dev and CRO | Master Elite | Mostly US |
| Homestead Studio | Shopify brands that want Klaviyo plus SEO and paid media | Master Elite | Not stated |
| Flowium | Brands that want an email-first programme | Master Elite | North America |
| Sticky Digital | Recharge subscription brands | Master Platinum | North America |
| Magnet Monster | A small team across email, SMS, WhatsApp and direct mail | Master Elite | Sale (UK) and Singapore |
1. Email Kong
We're a retention agency for Shopify brands, and most of our clients sell subscriptions or products people buy again. We run the whole Klaviyo account: the campaign calendar, design, copy, flows and SMS. For subscription brands we also work inside the subscription app on the cancel flow, failed payments and winback, which is where most subscribers are lost.
We're a Klaviyo Master Platinum Partner, ranked in the top 2.5% of partners worldwide, and a member of Klaviyo's Partner Advisory Council. Over 5 years we've worked with 140+ DTC brands in the US and UK, driven $59M+ in revenue attributed to Klaviyo at a 65.2x average return, and we're rated 4.5 on Trustpilot.
Kaori went from 3.3% to 19% of store revenue coming from Klaviyo. Penrose Skin went from 15.2% to 23.2% while the store more than tripled. At KittySpout, 46% of revenue is attributed to Klaviyo.
Your first flow is live within 72 hours of us getting access. After that every month runs on the EK Retention Cycle: fix what's leaking, test it, keep what wins. You get a shared Slack channel, a monthly report and call, and a reply within 1 working day. Retainers start from $5,000 a month.
Good fit if: you're a Shopify brand where repeat orders drive the business and you want a senior team that only does retention.
2. Underground Ecom
Underground Ecom is a Klaviyo Elite partner and was Klaviyo Agency of the Year 2025, per its listing. It runs email, SMS, WhatsApp and push for US and UK brands, alongside SEO, paid media and subscriber growth, in English, French, German and Italian. Clients include AG1, Huda Beauty, Oh Polly, Chilly's, Wild and Simba Sleep.
Good fit if: you're a large brand that wants retention and acquisition from one agency.
3. Chronos Agency
Chronos is a Klaviyo Elite partner with offices in Singapore and Sydney, running email, SMS and direct mail for brands of $10M to $500M a year across beauty, apparel, wellness, home, food and pet. Clients include The Oodie, Organifi, Truly Beauty and Kiyoko Beauty.
Good fit if: you're over $10M a year and want direct mail with your email and SMS.
4. Structured
Structured is a Klaviyo Platinum Master partner doing email and SMS for DTC brands on Shopify and other platforms. Clients include Eight Sleep, Fly By Jing, Health-Ade, Poo~Pourri, Hydrant and Mixtiles.
Good fit if: you're an established DTC brand and want an email and SMS specialist.
5. Fuel Made
Fuel Made is a Klaviyo Elite partner with a mostly US team that has worked only on Shopify since 2010. It gives each client a dedicated Klaviyo team and also does Shopify design, development and CRO. Clients include Beardbrand, Super7, Smidge and Tuft & Paw.
Good fit if: you're a $10M-$100M Shopify brand and want Klaviyo and site work from one place.
6. Homestead Studio
Homestead Studio is a Klaviyo Elite partner covering Klaviyo setup, strategy, email, SMS and data, plus SEO and paid media. Clients include HexClad, Girlfriend Collective, Casely and Theory11.
Good fit if: you want Klaviyo next to acquisition work.
7. Flowium
Flowium is a Klaviyo Elite partner in North America that says it has worked with 1,000+ brands since 2017. It runs email-first lifecycle programmes with SMS, WhatsApp, RCS and direct mail. Clients include Dr. Squatch, True Classic, Balsam Hill and Last Crumb.
Good fit if: you want an email-first programme from a large, established agency.
8. Sticky Digital
Sticky Digital is a Klaviyo Master Platinum retention agency with deep Recharge experience, including the Recharge API, bundles, loyalty and the customer portal. Clients include U Beauty, MUD\WTR, Nest New York and Cay Skin.
Good fit if: you sell subscriptions on Recharge.
9. Magnet Monster
Magnet Monster is a deliberately small Klaviyo Elite team in Sale, Cheshire and Singapore running email, SMS, WhatsApp and direct mail. Clients include Waterdrop, Laura Geller, Wild and Outerknown.
Good fit if: you want a boutique team across several channels.
How to choose
- Does your revenue sit in the range the agency works with?
- Can they show results from brands that sell like you do, subscription, replenishment or one-off?
- Who actually does the strategy, copy, design and builds?
- Can they show Klaviyo's share of store revenue before and after, with dates?
- What's in the monthly scope, and what's the minimum term?
For fees, read our Klaviyo agency pricing guide. If you sell subscriptions, our guides to a subscription retention agency and a Loop Subscriptions agency cover what to ask for.
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Sources
- Email Kong: Klaviyo directory
- Underground Ecom: Klaviyo directory, website
- Chronos Agency: Klaviyo directory
- Structured: Klaviyo directory
- Fuel Made: Klaviyo directory, website
- Homestead Studio: Klaviyo directory
- Flowium: Klaviyo directory, website
- Sticky Digital: Klaviyo directory, Recharge directory
- Magnet Monster: Klaviyo directory, website
