Flowium vs Underground Ecom
Short answer: Flowium is best for brands that want a US-based Klaviyo Master Elite agency. Underground Ecom is best for fast-growth and enterprise DTC brands that want full CRM strategy from a large team. Neither Flowium nor Underground Ecom publishes prices, so you need a quote from each on the same scope.
We run Huge Win Media, a third option on this page, so we are biased. Facts about Flowium and Underground Ecom come only from their own websites and their Clutch profiles.
At a glance
| Compared on | Flowium | Underground Ecom |
|---|---|---|
| What they do | Klaviyo agency for ecommerce brands, founded by Andriy Boychuk, known for its Klaviyo education content. | End-to-end email, SMS, and retention services from a large award-winning team, focused on fast-growth DTC. |
| Founded | 2017, by Andriy Boychuk | Not stated |
| Based in | New York, NY | Not stated (describes itself as one of the largest EMEA Klaviyo partners) |
| Team | Not stated on a page we could verify | 120+ retention marketers |
| Klaviyo partner tier | Klaviyo Master Elite (per Flowium's own content) | One of the largest EMEA Klaviyo partners (its own description) |
| Channels | Email and SMS on Klaviyo | Email, SMS, WhatsApp, and owned channels, plus CRM strategy |
| Pricing | Not published | Not published |
| Minimum | Not published | Not published |
| Guarantee | Not stated | Not stated |
| Track record | Not stated on a page we could verify | 150+ global clients, $165M in trackable sales claimed |
| Notable clients | Not verified | AG1, Osprey, VED, Surreal, Frive |
| Clutch | 4.9/5 from 23 reviews, min project $1,000+ | No Clutch profile found |
How they work
Flowium is a founder-led agency started by Andriy Boychuk in 2017 and known for its Klaviyo training content. It does not publish its team size or prices on a page we could verify, so you will learn its working model on a call.
Underground Ecom has 120+ retention marketers and sells a full program: CRM audit and roadmap, retention strategy, creative and execution, automations, and SMS and WhatsApp management. It focuses on fast-growth DTC brands.
Pricing
Flowium: Not published. Underground Ecom: Not published.
Neither Flowium nor Underground Ecom publishes prices, so you need a quote from each on the same scope. Prices change, so confirm on a call before you decide.
Klaviyo partner tier and channels
Flowium lists its Klaviyo status as Master Elite (per Flowium's own content). Underground Ecom lists its Klaviyo status as One of the largest EMEA Klaviyo partners (its own description).
Flowium covers email and SMS on Klaviyo. Underground Ecom covers email, SMS, WhatsApp, and owned channels, plus CRM strategy.
What reviewers say
Flowium has 4.9/5 from 23 reviews, min project $1,000+ on Clutch. Points reviewers raise most often:
- "issues with account management transitions"
- "more retroactive updates to existing content"
- "occasional miscommunications regarding meeting times"
Underground Ecom: no Clutch profile found.
Read the full reviews: Flowium on Clutch
Who should choose which
Choose Flowium if
- You want a US-based agency working in your time zone.
- You want a Klaviyo Master Elite partner.
- You value an agency whose founder publishes a lot of Klaviyo training.
Choose Underground Ecom if
- You are a large or fast-scaling brand and want a 100+ person retention team.
- You want CRM audits and strategy, not just email execution.
- You sell mainly in Europe and want an EMEA-focused partner.
A third option: Huge Win Media
Huge Win Media is about a dozen people working only in Klaviyo. Each client keeps the same marketers, writers, and designers every month. Week 1 is a full audit of every flow, campaign, and segment. Week 2 rebuilds the highest-impact flows. Week 3 starts the campaign calendar. After that it runs on weekly syncs, monthly reporting, and a quarterly A/B testing roadmap.
Huge Win Media is best for established brands with no one in-house on email, ready to put $1,000 to $2,000 a month into it. Pricing: From $1,000/mo. Campaigns $100 to $200 per email by format. Flows quoted after a free audit, from $3,500. Lower rate if your team runs strategy or account management. It works only in Klaviyo, is not a Master Elite partner, and has no Clutch profile yet.
| Compared on | Flowium | Underground Ecom | Huge Win Media |
|---|---|---|---|
| Best for | Brands that want a US-based Klaviyo Master Elite agency | Fast-growth and enterprise DTC brands that want full CRM strategy from a large team | Established brands with no one in-house on email, ready to put $1,000 to $2,000 a month into it |
| Pricing | Not published | Not published | From $1,000/mo. Campaigns $100 to $200 per email by format. Flows quoted after a free audit, from $3,500. Lower rate if your team runs strategy or account management |
| Minimum | Not published | Not published | No minimum term on monthly plans. One-off flow builds have no ongoing commitment |
| Klaviyo tier | Klaviyo Master Elite (per Flowium's own content) | One of the largest EMEA Klaviyo partners (its own description) | Klaviyo Partner (not Master Elite) |
| Clutch | 4.9/5 from 23 reviews, min project $1,000+ | No Clutch profile found | No Clutch profile yet |
More comparisons
- Huge Win Media vs Flowium
- Huge Win Media vs Underground Ecom
- Flowium alternatives
- Underground Ecom alternatives
Questions
Is Flowium better than Underground Ecom?
Neither is better for everyone. Flowium is best for brands that want a US-based Klaviyo Master Elite agency. Underground Ecom is best for fast-growth and enterprise DTC brands that want full CRM strategy from a large team.
Which is cheaper, Flowium or Underground Ecom?
Neither Flowium nor Underground Ecom publishes prices, so you need a quote from each on the same scope. Flowium: Not published. Underground Ecom: Not published. Checked October 2026.
Is there an alternative to Flowium and Underground Ecom?
Yes. Huge Win Media is best for established brands with no one in-house on email, ready to put $1,000 to $2,000 a month into it, with monthly plans from $1,000 and flow builds from $3,500. It works only in Klaviyo and is not a Master Elite partner.
More agency comparisons and buying guides
Sources and how this page was checked
Facts about other agencies come only from their own websites, checked October 2026. Where an agency does not publish a price or number, we say so instead of guessing. Spot something out of date? Email emma@hugewinmedia.com and we will fix it.
Sources: Flowium: 15 best Klaviyo agencies (Flowium blog) · Flowium: email marketing agency pricing (Flowium blog) · undergroundecom.com homepage · Huge Win Media pricing · About Huge Win Media · Case studies