Every agency on this list is in Klaviyo's partner directory and is based in the UK. Some run your Klaviyo account week to week and some fold it into a wider ecommerce brief, so each entry says who it suits.
The shortlist at a glance
| Agency | Good fit for | Klaviyo listing | Based |
|---|---|---|---|
| Email Kong | Shopify brands that want Klaviyo run every week, subscription brands included | Master Platinum | London |
| Underground Ecom | Larger brands that want retention plus acquisition | Master Elite | UK |
| Enchant Agency | Larger brands that want one CRM team across many channels | Master Platinum | London |
| PAASE | Brands that want AI-led personalisation and data work | Master Elite | Milton Keynes |
| Get Better | Brands that want full account management from a small team | Master Elite | North Devon |
| Magnet Monster | Email, SMS, WhatsApp and direct mail from a small team | Master Elite | Sale (Cheshire) and Singapore |
| VALIX | Mid-market and enterprise brands that want predictive segmentation | Master Platinum | London |
| ElliotDigital | Shopify brands that want email and SMS only | Master Platinum | London |
| Swanky | Shopify Plus brands that need a store build too | Platinum | UK, Australia and France |
1. Email Kong
We're a UK Klaviyo agency in London, a 2-minute walk from Klaviyo's London office, and we work with Shopify brands in the UK and US. We run the whole account: the campaign calendar, design, copy, flows and SMS. Most of our clients sell subscriptions or products people buy again, so we also work inside Loop, Appstle and Checkout Champ on the cancel flow, failed payments and winback.
We're a Klaviyo Master Platinum Partner, ranked in the top 2.5% of partners worldwide, and a Loop Platinum Partner. Our founder, Bogdan Mihalache, is a member of the Klaviyo Partner Advisory Council, one of 35 members worldwide. Over 5 years we've worked with 140+ DTC brands, run 500+ Klaviyo audits and driven $59M+ in revenue attributed to Klaviyo at a 65.2x average ROI, and we're rated 4.5 on Trustpilot.
Kaori went from saving 4.3% to 60% of subscribers who tried to cancel, and 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.
We're an AI-first retention agency, with about 120 flow A/B tests live across our clients. Your first flow is live within 72 hours of us getting access, and after that you get a shared Slack channel, 2 Slack updates every week, a monthly report and call, and a quarterly call with our founder. Retainers start from $5,000 a month, with a 3-month minimum.
Good fit if: you're a UK or US Shopify brand and want a senior team that runs Klaviyo every week and can show the numbers.
2. Underground Ecom
Underground Ecom is a UK retention agency and Klaviyo Master Elite partner, and its listing says it was Klaviyo Agency of the Year 2025. It manages the whole Klaviyo account across email, SMS, WhatsApp and push, alongside SEO, paid media and subscriber growth, in English, French, German and Italian. Clients include AG1, Huda Beauty, Virgin Experience Days, Osprey, Simba Sleep and Wild.
Good fit if: you're a large brand that wants retention and acquisition from one agency.
3. Enchant Agency
Enchant is a London email and eCRM agency with a team of 30 and a Klaviyo Master Platinum partner for 9 years, per its listing. It won Klaviyo's award for Most Innovative Use of Automation in 2023 and covers onboarding, audits, campaigns, integrations and AI for CRM. Clients include QVC, Victorinox, Sealskinz, Herbalife, Cox & Cox and Hampers.com.
Good fit if: you're a larger brand and want one CRM team across many channels.
4. PAASE
PAASE is a Klaviyo Master Elite agency founded in 2019 and based in Milton Keynes. Its listing says it was the first UK agency to reach Klaviyo Platinum Master and the first Elite Master partner based in EMEA. It focuses on first-party data, predictive segmentation and AI-led personalisation. Clients include Curlsmith, Dr Martens, Laura Ashley, Wattbike, Wild Nutrition and Union Coffee.
Good fit if: you want personalisation and data work led by an experienced Klaviyo team.
5. Get Better
Get Better is a Klaviyo Master Elite agency based in North Devon. It offers full account management with monthly reporting, flows, campaigns across email, SMS, WhatsApp and RCS, Klaviyo data and Customer Hub setup, and audits in several sizes. Clients include PerfectTed, Absolute Collagen, Lily & Roo, Green People and Stone Creek Coffee.
Good fit if: you want a small team running the whole Klaviyo account with a set monthly report.
6. Magnet Monster
Magnet Monster is a Klaviyo Master Elite agency, small by design, with offices in Sale, Cheshire and Singapore. It runs email, SMS, WhatsApp and direct mail, says it has worked with 300+ DTC brands, and offers a subscription audit. Clients include Waterdrop, Laura Geller, Wild, Outerknown and Spotlight Oral Care.
Good fit if: you want several channels run by one small team.
7. VALIX
VALIX is a London lifecycle agency and Klaviyo Master Platinum partner, built by people with 15+ years in lifecycle marketing. It works with mid-market and enterprise brands on predictive segmentation, RFM, single customer views and AI-generated content inside Klaviyo. Clients include Curlsmith, Elizabeth Arden, Okanui and Cocopup London.
Good fit if: you're a larger brand and want data and segmentation at the centre of your Klaviyo.
8. ElliotDigital
ElliotDigital is a London email and SMS agency and Klaviyo Master Platinum partner. Its small team covers strategy, copy, design and execution, and it offers free audits. Clients include SURREAL, HUX, Personalised Co and Cornelia James.
Good fit if: you're a Shopify brand and only want email and SMS.
9. Swanky
Swanky is a full-service Shopify Plus agency and Klaviyo Platinum partner with offices in the UK, Australia and France. It does replatforming, subscription builds, CRO and Klaviyo work, from migrations and audits to campaign management, on monthly retainers or one-off projects. Clients include HelloFresh, Kent Brushes, Bouclème, Natural Instinct and Shackleton.
Good fit if: you're on Shopify Plus and want the store build and Klaviyo from one agency.
How to choose
- Is the agency a Klaviyo Master partner, who runs the account for you, or an Advisor, who mostly advises?
- Who actually does the strategy, copy, design and builds?
- Can they show Klaviyo's share of store revenue before and after, with dates?
- If you sell subscriptions, will they work inside your subscription app?
- What's the minimum term and notice period?
If you want a team you can meet, see the best Klaviyo agencies in London. If you sell subscriptions, read the best Klaviyo agencies for subscription brands, and for a wider view, the best retention marketing agencies for ecommerce. For fees, see our Klaviyo agency pricing guide.
Get a free Klaviyo audit
Send us access and we'll show you what your Klaviyo account is missing. You get a recorded walkthrough and a fix plan in order of impact within 48 hours, reviewed by our founder. Get your free Klaviyo audit.
Sources
- Email Kong: Klaviyo directory
- Underground Ecom: Klaviyo directory, website
- Enchant Agency: Klaviyo directory, website
- PAASE: Klaviyo directory, website
- Get Better: Klaviyo directory, website
- Magnet Monster: Klaviyo directory, website
- VALIX: Klaviyo directory, website
- ElliotDigital: Klaviyo directory, website
- Swanky: Klaviyo directory, website
- Klaviyo partner tracks and tiers: Klaviyo Academy
