Best Klaviyo Agencies in the UK [2026]

Search "Klaviyo agency UK" and you'll find two kinds of results: giant Shopify agencies that treat email as an add-on line item, and one-person consultancies that built a welcome flow once. Neither is what a growing UK brand actually needs.

The UK is one of the most mature eCommerce markets in the world. Boxing Day rivals Black Friday, PECR sits on top of GDPR, and UK consumers are ruthless about hitting unsubscribe on lazy email. That combination punishes generic Klaviyo work harder than almost any other market.

So we ranked the agencies that can genuinely handle it. Some are UK-based, some serve UK brands from elsewhere, and all of them do real email marketing work rather than template-and-invoice.

Short on Time? Our Top Pick Is GOSH Digital

Yes, we're recommending ourselves, and yes, we're based in Dubai rather than London. Book a free Klaviyo audit and in 20 minutes we'll show you exactly what's wrong with your Klaviyo account. No pitch, no pressure. We're a Klaviyo Gold Partner that's driven $23M+ in revenue for 150+ eCommerce brands, and the Dubai-to-UK time difference is just 3 to 4 hours, which means we work your working day.

How We Evaluated These Agencies

The same framework we use in our USA and Canada rankings, with two UK-specific additions:

• Klaviyo Partner tier. Gold, Silver, or basic? The tier reflects account volume and demonstrated results, not marketing claims.
• Revenue attribution. Can they show Klaviyo-attributed revenue as a percentage of total store revenue? 25-40% is the benchmark for a healthy email and SMS program.
• Flow architecture. 5 template flows, or 15-25 flows with conditional splits, A/B tests, and behavioural triggers?
• GDPR and PECR fluency. Do they understand the soft opt-in, consent records, and lawful basis? In the UK this is not optional, and the ICO does issue fines.
• UK calendar awareness. Boxing Day, bank holiday weekends, Sunday-evening browsing peaks. A US-calendar campaign plan leaves UK revenue on the table.
• Reporting tied to revenue. Revenue per recipient and attributed revenue per flow, not open-rate screenshots.

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1. GOSH Digital: The Gold Partner That Works Your Hours

Best for: UK eCommerce brands doing £400K-£40M who want data-led Klaviyo management from a Gold Partner

Pricing: Custom, starting around $2,500/month for Klaviyo management

Key strength: We model your customer data before building anything, so your flows are built on what your numbers say rather than on templates.

Let's deal with the location question first. We're in Dubai. For US clients that means overnight delivery; for UK clients it barely registers, because Dubai is only 3 to 4 hours ahead of the UK. When you start your day in Manchester or London, we've already been at our desks since your early morning, and we're still working when you wrap up. Calls are easy, turnarounds are same-day, and nothing about the relationship feels remote.

What actually separates us is the process. Before we build a single flow, we pull your customer data and model it: purchase frequency curves, cohort behaviour, average days between orders, and revenue concentration by segment. That analysis tells us which flows are missing, which segments are underserved, and which campaigns would move revenue fastest. Most agencies skip straight to "you're missing a browse abandonment flow" and start invoicing. We'd rather find out why your repeat rate is 18% when your category benchmark is 32%, and fix that.

On the compliance side, we build UK accounts around UK rules. Consent collection is configured properly at capture, the PECR soft opt-in is applied where it legitimately can be, and suppression groups are handled so you're never one export away from an ICO complaint. It's unglamorous work that pays for itself the first time you don't have a problem.

We're a Klaviyo Gold Partner, a tier reached by roughly 3% of the partner directory and verified by Klaviyo on results rather than coursework. If you want to see what a real audit looks like, book a call and we'll walk through your account live.

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2. Blend Commerce: The UK Retention Specialists

Best for: UK Shopify brands that want a retention-first partner focused on email, SMS, and customer lifecycle

Pricing: Typically £2,000-£5,000/month depending on scope

Key strength: Genuine retention focus rather than email as a side dish to a dev retainer

Blend Commerce built their reputation as a Shopify agency and have steadily moved toward what they now do best: retention. Their Klaviyo work sits inside a broader customer-lifecycle practice covering flows, campaigns, and the on-site journey that feeds the list in the first place.

That framing matters. A lot of UK agencies treat Klaviyo as "the emails," disconnected from signup experience, offer strategy, and post-purchase journey. Blend joins those dots, and their strategy work reflects a team that has seen many Shopify accounts rather than a few.

The trade-off is capacity. They're a boutique rather than a volume shop, so if you need 20 campaigns a month shipped at pace, ask hard questions about bandwidth before signing.

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3. Velstar: The Shopify Plus Agency With Real Email Capability

Best for: UK Shopify Plus brands that want store build, CRO, and email under one roof

Pricing: Project fees for builds; retainers typically from £3,000/month

Key strength: Deep Shopify Plus technical work with an in-house marketing team, so email and site changes don't fight each other

Velstar is one of the UK's better-known Shopify Plus agencies, and unlike most dev-led shops, their marketing arm is real rather than decorative. For brands mid-replatform or planning one, having the same team own the store build and the Klaviyo rebuild removes a whole category of vendor finger-pointing.

The honest caveat is the same one we'd give any full-service agency: email is one practice among several. If your only need is world-class Klaviyo management, a specialist will usually go deeper. If you need the store and the email program rebuilt together, Velstar is one of the strongest UK options.

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4. Eastside Co: The Established UK Shopify Shop

Best for: UK brands that want a long-established Shopify agency with email marketing as part of a wider growth engagement

Pricing: Retainers typically from £2,500/month; project work priced separately

Key strength: Longevity and breadth. They've been in UK eCommerce long enough to have seen most problems before.

Eastside Co has been building and growing Shopify stores since the early days of the platform in the UK. Their service list spans design, development, SEO, paid, and email, with Klaviyo sitting inside the marketing practice.

For brands that want one accountable partner across channels, that breadth is the appeal. For brands that specifically want the deepest possible Klaviyo bench, it's the limitation. Ask to meet the person who will actually run your email account, and ask for Klaviyo-specific results rather than agency-wide case studies.

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5. Soar With Us: The Aggressive Growth Shop

Best for: UK DTC brands scaling hard on paid who want email built to convert that traffic

Pricing: Typically £2,000-£6,000/month depending on channels

Key strength: They think in blended CAC and treat email as the margin-saver it is, not a standalone channel

Soar With Us made their name in Leeds on aggressive paid media growth for DTC brands, and their email practice exists because their founders understand something many paid-first agencies never learn: ad accounts scale further when the email backend converts the traffic you already paid for.

If you're spending heavily on Meta and TikTok and your flows are weak, that combination of paid and email under one roof is genuinely useful. The flip side is that email is the supporting act in their model. Brands that want retention-led strategy, rather than acquisition-led with retention support, should weigh that.

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6. Underwaterpistol: The Migration and Lifecycle Team

Best for: UK and EU brands replatforming to Shopify who need email infrastructure rebuilt in the process

Pricing: Project-led; ongoing retainers scoped case by case

Key strength: Strong migration pedigree, which matters because replatforming is where email programs quietly break

Underwaterpistol is a long-running Glasgow-born Shopify agency with a solid record of complex migrations. That matters for email more than most brands realise: replatforming is exactly the moment integrations, signup sources, and historical data get mangled, and Klaviyo accounts often limp for months afterward.

Having a team that treats email data as a first-class migration workload rather than an afterthought is the reason they're on this list. As with the other full-service entries, probe the depth of the ongoing Klaviyo management before committing to a long retainer.

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7. Flowium: The US Specialist That Serves UK Brands

Best for: UK brands that want a pure-play Klaviyo specialist and don't mind US hours

Pricing: Roughly $2,000-$6,000/month

Key strength: They do Klaviyo and only Klaviyo, with the depth that focus buys

Flowium appears in our global ranking for good reason: a 100% Klaviyo-focused agency with hundreds of eCommerce accounts behind them. They serve UK brands, and the work itself is strong.

The friction is the clock. A US East Coast agency starts its day when the UK is finishing lunch, which compresses collaboration into a narrow late-afternoon window. Plenty of brands make it work with async communication. But if you've been frustrated by a partner you can never get on a call with, factor the time zone into the decision honestly.

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How to Choose: Five Questions That Expose Depth Fast

1. "What's the first thing you do in my Klaviyo account?" The right answer starts with an audit of deliverability, consent configuration, and flow revenue attribution. The wrong answer starts with building things.

2. "How do you handle PECR and the soft opt-in?" If the answer is a blank look, walk away. UK email law is not a footnote.

3. "How many flows should my account have?" Good agencies say "it depends" and explain on what. Bad agencies quote a fixed number.

4. "Show me Klaviyo-attributed revenue for a comparable brand." Not open rates. Not "engagement." Revenue, as a percentage of store total. Healthy accounts run 25-40% from email and SMS combined.

5. "What does your reporting look like?" You want revenue per recipient and per-flow attribution in plain English, monthly, without asking twice. Costs and what drives them are covered in our Klaviyo agency pricing guide.

Related Reads

• Best Klaviyo Agencies for eCommerce Brands
• Best Klaviyo Agencies in the USA
• Best Klaviyo Agencies in Canada
• How Much Does a Klaviyo Agency Cost?
• Klaviyo Agency: The Essential Guide for eCommerce Brands

The Bottom Line

The UK has no shortage of agencies that will "do your emails." It has very few that will treat your Klaviyo account like the revenue engine it should be: audited before it's touched, built on your data rather than templates, compliant without being asked, and reported in pounds rather than open rates.

Every agency on this list clears that bar in its own way. Pick based on what your account needs right now: a retention specialist, a build-and-email partner, or a data-led Gold Partner working your hours.

Book a free Klaviyo audit with GOSH Digital and we'll walk through your account live, on UK-friendly hours, and show you exactly where the revenue is hiding.