Underground Ecom

Key points

• Category: Agencies: eCommerce retention
• Pricing: Paid
• Best for: Brands looking for an agency partner for Klaviyo-led retention and lifecycle work for DTC and eCommerce brands.
• Klaviyo Elite Master, Agency of the Year 2025
• 8-10 figure brands (AG1, Huda Beauty)
• Based in UK

What Underground Ecom is

Underground Ecom is a London-founded (2017) email and SMS retention marketing agency holding Klaviyo's highest Elite Master partner tier and named Klaviyo's EMEA Agency Partner of the Year for 2025. The agency has worked with well-known consumer brands including AG1, Virgin, Huda Beauty and Oh Polly, and runs a team spread across multiple countries.

Services cover end-to-end Klaviyo account management: flow strategy and automation, campaign management, segmentation and list management, SMS marketing, A/B testing, data analysis and advanced Klaviyo Data Platform (CDP) implementation for larger brands. It works across both managed retainer engagements and defined project-based scopes.

It sits in the agencies: ecommerce retention part of an email stack - klaviyo-led retention, lifecycle and sms teams for dtc brands. In practice it is the right pick when your priority is: brands looking for an agency partner for klaviyo-led retention and lifecycle work for dtc and ecommerce brands.

What it does well

The capabilities teams rely on most are klaviyo elite master, agency of the year 2025, 8-10 figure brands (ag1, huda beauty), based in uk. Taken together these cover the day-to-day work in this category, and they are the features worth testing during a trial rather than reading about.

Its Klaviyo Agency Partner of the Year EMEA 2025 recognition and Elite Master ranking place it among the highest-tier Klaviyo partners globally, backed by a track record with large, recognizable consumer brands.

In real use the strongest points people report are specialist team rather than a generalist marketing shop; hands-on execution: strategy, creative and campaign delivery.

Key features

• Klaviyo Elite Master, Agency of the Year 2025
• 8-10 figure brands (AG1, Huda Beauty)
• Based in UK
• Specialist team rather than a generalist marketing shop
• Hands-on execution: strategy, creative and campaign delivery

Pricing tiers

Underground Ecom is a paid product. Custom retainer or project-based pricing scaled to brand revenue tier (from $1M up to $500M+ annual revenue bands listed in its Klaviyo partner profile), quoted directly rather than published as a rate card.

Pricing pages move often, so confirm the current figures with the vendor before you budget. The number worth modelling is not the licence fee on its own but the cost per delivered email once bounces, suppressed contacts and spam-foldered sends are taken out.

Ideal customer profile

• Best fit: Brands looking for an agency partner for Klaviyo-led retention and lifecycle work for DTC and eCommerce brands.
• Where it sits in the stack: Agencies: eCommerce retention - klaviyo-led retention, lifecycle and sms teams for dtc brands.
• Budget profile: Paid - suited to teams comfortable with this commercial model.
• Probably not for you if: retainer pricing - not a self-serve tool would block your team.

What it connects to

Underground Ecom is commonly wired into Klaviyo, Shopify, Shopify Plus, BigCommerce, Magento, Salesforce Commerce Cloud, SMS/MMS/RCS platforms, WhatsApp and Mobile push providers. Check that the specific objects and events you rely on are covered, not just that a logo appears on the integrations page - shallow connectors are a frequent source of rework.

Where it falls short

No tool in this space is complete on its own. With Underground Ecom the trade-offs to plan around are retainer pricing - not a self-serve tool; deliverability and sending reputation usually stay your responsibility. None of these are reasons to avoid it - they are the gaps another layer of your stack needs to fill.

The agency's brand roster skews toward established, higher-revenue ecommerce companies, so smaller or newer stores may find the engagement model and pricing geared toward bigger budgets.

A useful test before committing: send a real campaign through your intended setup, then check where it actually lands across Gmail, Outlook, Yahoo and your customers' corporate filters. Tooling that looks identical on a feature list often behaves very differently once reputation and authentication are involved.

The essentials

Category

Agencies: eCommerce retention

Pricing model

Paid

Vendor

www.undergroundecom.com

G2 rating

Not listed

Best for

Brands looking for an agency partner for Klaviyo-led retention and lifecycle work for DTC and eCommerce brands.

Works alongside Warmy

Yes - warm-up, placement, DMARC

How it fits a deliverability stack

Deliverability is decided by four things: the reputation of the sending domain and mailbox, the quality of the list, correct SPF, DKIM and DMARC authentication, and proof of where mail actually lands. Underground Ecom covers part of that picture. The mistake most teams make is buying four separate products for those four jobs and still having no single place that tells them whether the last campaign reached the inbox.

Warmy runs warm-up, inbox placement testing, email verification and DMARC monitoring as one platform, which is why Underground Ecom usually sits alongside it rather than against it: it keeps doing what it is good at, while reputation, placement and authentication are handled in one loop.

Underground Ecom lists deliverability as one of its specialties within Klaviyo account management, focused on segmentation and sending practices rather than a standalone deliverability product.