What an eCommerce Email Marketing Agency Does, and How to Pick One

An eCommerce email marketing agency runs the channels you already own: the automated flows that fire off customer behavior, the campaign calendar, SMS, list growth, deliverability, and the reporting that says whether any of it made money. Hayes Media does that work for eCommerce brands scaling past $10M a year, either next to our Meta creative and media buying or on its own. Hire one when your list is big enough that a badly built welcome flow costs you more than the agency does, and when nobody in house owns the send calendar.

What an eCommerce email marketing agency actually does

Most brands think they're buying emails. They're buying a system that decides who gets what message, when, and at what margin.

The work splits into six jobs.

• Flows. The automations that run without anyone pressing send: welcome, abandoned browse, abandoned cart, abandoned checkout, post purchase, winback, replenishment, VIP. These earn while you sleep and they compound with traffic.
• Campaigns. The scheduled sends: launches, promotions, education, restocks, and the peak calendar. This is where margin quietly leaks.
• SMS. A separate channel with its own consent rules and its own economics. Copying email into SMS wastes it.
• List growth. Onsite capture, offers, quizzes, and the placement rules that decide how many new subscribers arrive and how good they are.
• Deliverability. Sending reputation, authentication, sunsetting rules, and engagement segmentation. When this breaks, every other job on this list stops working.
• Reporting. The number that decides whether the program is winning, and who gets to pick it.

That last one separates agencies more than any tactic. A program can grow email revenue and shrink the business, if it grows by discounting to people who were going to buy anyway. We judge retention on lifetime gross profit to CAC: the profit a customer produces across their life, against what it cost to acquire them. CAC is customer acquisition cost. If you want the math behind that scoreboard, we wrote it out in eCommerce unit economics.

What Hayes Media does

Our retention practice sits at email.hayesmedia.co. Here is the scope, in the order we usually build it.

• Audit the account first. Flow logic, trigger conditions, segmentation, exclusion rules, sending reputation, and what each flow currently earns. We publish our own version of this as a email marketing audit walkthrough so you can run it yourself before you call anyone.
• Rebuild the core flows. The set that carries most automated revenue for a Shopify brand, built with real branching rather than one linear path. We break the build down in Klaviyo email flows.
• Rewrite the welcome series. The first sequence a subscriber ever gets, and the one most brands treat as a coupon delivery mechanism. See welcome series email.
• Fix cart and checkout recovery. Separate browse, cart, and checkout triggers, with copy that matches how close the person got. Examples in abandoned cart email examples.
• Build the second purchase path. Post purchase education, review requests, cross sell, and replenishment timing tied to the product, not to a calendar guess. See post purchase email flow examples.
• Run the campaign calendar. Segmented sends, offer strategy, peak planning, and a promotional cadence that protects gross margin instead of training the list to wait for a discount.
• Run SMS as its own channel. On the retention page we put it plainly: "Most SMS is just a copy of email. We play to the uniqueness of the channel, often doubling SMS revenue contribution."
• Grow the list. Capture, offers, and placement. The same page states: "We grow client lists 3.1x faster. More subscribers, more revenue, lower CAC."
• Own deliverability. Authentication, engagement tiers, sunsetting, and reputation monitoring, so the sends you plan actually arrive.
• Report on profit, not channel vanity. Revenue by flow and campaign, plus the contribution view that connects retention back to acquisition. Wider context in eCommerce retention marketing.
• Loyalty, subscription, and referral programs. The retention page lists all three alongside email and SMS, for brands where repeat purchase is the whole business.

Two commercial terms are stated on that page and worth repeating: "No onboarding fees. No lock-in contracts. No junior marketers."

Who this is for, and who it is not for

This is for you if:

• You're scaling past $10M a year. That's the band the team is built for, stated on hayesmedia.co: "Meta ad creative, Meta media buying, Email & SMS. Take all three or just the one you need, and scale past $10M/year."
• You want a standalone retention partner. You can take email and SMS on their own.
• Your acquisition costs have climbed and the fix has to come from the back end. When CAC rises, the only lever left is what each customer is worth after the first order.
• You have a list you're barely mailing. Dormant lists are the cheapest revenue in the business, if deliverability is still intact.
• Nobody owns the calendar. A marketing coordinator sending when they remember is the most common version of a broken program.

This is not for you if:

• You're pre product market fit. Retention amplifies a product people want to buy twice. It cannot manufacture that.
• Your list is tiny and traffic is flat. Flows need volume passing through them. Fix traffic first, or the best built welcome series earns almost nothing.
• You want someone to press send on what you write. That's a freelancer, and it's a fine purchase. It just isn't this.
• You want the cheapest option. We published a ranked comparison of the field, including agencies with lower entry points than ours, at best email marketing agencies for eCommerce.
• Your brand has no reason for a second purchase. Some categories genuinely are one and done. Say so, and put the money into acquisition.

What it costs to get email wrong

No invented figures here, because the damage shows up as mechanism, not as a tidy percentage.

Deliverability decay. Mailing the whole list to hit a revenue number raises complaints and non opens. Mailbox providers respond by filtering more of your mail. The brand sends more and reaches fewer people, so it sends more again.

Discount dependency. Every send with a code teaches the list to wait. Email revenue looks fine on the dashboard because the orders still happen, at a worse gross margin, from customers who were going to buy anyway. The channel takes credit for demand it did not create.

Flows firing on the wrong trigger. A cart flow that treats a browse as a cart, or a replenishment reminder timed to the wrong product cycle, sends the right message to the wrong person. The subscriber reads it as noise.

Bad list growth. A discount popup shown to everyone buys you subscribers who came for the code. They inflate list size and drag engagement down with them.

No profit view. Without lifetime gross profit to CAC, nobody can tell which of the four problems above is currently happening, because channel revenue can rise through all of them.

How an engagement runs

The sequence is the same on every account. We do not skip the first step, because everything after it depends on what the first step finds.

1. Audit. We go through the account: every flow and its trigger logic, segmentation, exclusions, sending reputation, list health, the campaign history, and what each piece currently earns. The retention page describes the call the same way: "We'll audit your current setup, show you what's leaking revenue."
2. Agree the scoreboard. Before anything is built, we agree what we're judging the program on and where the number comes from. Lifetime gross profit to CAC, with channel revenue as a supporting view rather than the verdict.
3. Fix deliverability. Authentication, engagement tiers, and sunsetting rules go in before volume goes up. Building on a damaged sending reputation wastes the build.
4. Rebuild the flows, highest earner first. Welcome, then cart and checkout recovery, then post purchase and the second purchase path, then winback and replenishment. Each one ships live rather than waiting for the full set.
5. Take over the campaign calendar. Segmented sends against a planned offer strategy, with the promotional cadence set deliberately instead of reactively.
6. Layer SMS. Built as its own channel with its own message types, not a copy of the email calendar.
7. Turn on list growth. Capture and offers come after the flows are good, because more subscribers into a broken welcome series just wastes them.
8. Report and iterate. What earned, what didn't, what changes next, and what that did to the profit line.

The proof

Every figure below is quoted exactly as it appears on our retention page, email.hayesmedia.co. Nothing here is rounded or restated.

Track record on that page:

• "Trusted by 50+ eCom brands"
• "$500M+ Client revenue driven" and "Millions in monthly retention revenue across our client portfolio."
• "15x Average ROI" and "We obsess over the metrics that actually move the business."
• "8 yrs Retention expertise" and "Service, communication, and execution dialed in since 2016."
• "We grow client lists 3.1x faster. More subscribers, more revenue, lower CAC."

The four result blocks published on the same page:

• All-Time Email Revenue. Figures as published: "12,400% Revenue Growth" / "150% ROAS Increase".
• All-Time SMS Revenue. Figures as published: "419% Revenue Growth" / "3.3% Conv. Rate Lift".
• Email and SMS share. Figures as published: "+218% Email Revenue YoY" / "39.56% of Revenue from Email & SMS" / "59.4% Open Rate".
• Retention share. Figures as published: "0% → 59% of Revenue from Retention" / "+140% Total Revenue YoY" / "54% Returning Customer Rate".

ROAS is return on ad spend. Two of those are worth reading closely, because they show the two different jobs retention does. The retention share block starts at zero, which means the brand had no retention revenue at all, and the same account shows "+140% Total Revenue YoY" and a "54% Returning Customer Rate". Total revenue and returning customer rate are business numbers, not channel numbers. That's the version of a result we care about.

What the clients say about the retention work, from the same page:

• "Retention went from an afterthought to nearly 60% of our revenue." PJ Ebadi, E-commerce Lead, KiZE
• "They came in right before BFCM and rebuilt our retention engine fast. They feel like an extension of my own team." Zack Brust, Founder & CEO, Del Campo
• "Month over month, our sales keep climbing. Their retention work has been one of the biggest levers for our growth." Oscar Adelman, Founder & CEO, Remi

One honest limit, the same one we gave ourselves in our ranked list: those case studies are published by us, on our own site. We have no third party review profile.

How to judge any email agency

Run this on us and on everyone else you're shortlisting. It takes one call.

1. Ask what number they'll be judged on. If the answer is email attributed revenue and nothing else, ask what stops them from discounting their way to it. A good answer names gross profit or contribution.
2. Ask who touches the account. Names and seniority, not a team page. Ask how many accounts that person carries.
3. Ask who owns deliverability. If nobody answers clearly, nobody owns it, and it will break the first time they push volume.
4. Ask to see a flow map before you sign. Any competent shop can sketch what they'd build for your catalog and your repeat cycle. Vagueness here is the tell.
5. Ask about their discount policy. Specifically: what percentage of sends carry a code, and what they do when revenue is behind plan.
6. Ask how segmentation works. Engagement tiers, purchase history, and product affinity, or one big list with a few tags.
7. Ask what happens to your assets if you leave. Flows, templates, and segments should stay in your account, under your login.
8. Ask what they won't do. An agency that serves everyone at every size has not thought about fit.
9. Ask for a number that isn't channel revenue. Returning customer rate, repeat purchase rate, or retention share of total revenue. If they've never reported one, they've never been asked to.