For an online store, email is usually the highest-margin channel it owns, because the audience is already yours and the cost per send is close to nothing. That is exactly why the category attracts so many agencies making similar promises about revenue share. An email marketing agency for ecommerce earns its fee in two places: the automated flows that run without anyone touching them, and the campaign calendar that keeps the list engaged without burning it. Most of the money is in the first and most of the visible work is in the second. This guide explains what the work actually is, how agencies price it, the deliverability questions that decide whether any of it works, and how to check a candidate before you sign anything.
Flows first, campaigns second
The automated sequences are where the durable revenue sits: the welcome series for new subscribers, the abandoned browse and abandoned cart sequences, post-purchase onboarding and review requests, replenishment reminders for consumables, and winback for lapsed buyers. Built once and tuned quarterly, these run against every visitor forever. Campaigns, the newsletters and promotions, produce visible spikes and are what most agencies show in a pitch, but a store with excellent campaigns and no flows is leaving the reliable half of the channel on the floor. A good proposal therefore starts by auditing which flows exist, which are misconfigured and which are missing, and only then discusses a sending calendar. If the first slide is a content calendar, the agency is selling the easier half.
Deliverability is the whole game
Everything else is decoration if the mail lands in spam. That means list hygiene (suppressing non-openers rather than blasting the whole file), authentication set up properly on your sending domain, a warmed sending reputation, and a consent trail for every address. It also means legal compliance: the Federal Trade Commission's CAN-SPAM compliance guide sets out the baseline for commercial email in the US, including honest headers and subject lines, a clear opt-out that is honored promptly, and a valid physical address in the message. Ask any candidate agency to explain what it would do in the first month about authentication, segmentation and suppression. An agency that answers with design mockups instead has never had to rescue a domain reputation, and you do not want to be the account where it learns.
How agencies price this work
There are three common shapes. A flat monthly retainer covers a defined number of campaigns plus flow maintenance, and is the easiest to compare between vendors. A percentage of attributed email revenue aligns incentives on paper but rewards over-sending and depends entirely on an attribution window the agency usually chooses, so read that definition closely. A hybrid, a smaller base plus a smaller share, is common and reasonable. Setup or build phases are usually quoted separately, since constructing a full flow set is a project rather than a monthly task. Whatever the shape, ask for the deliverables per month in writing, who writes the copy, who designs, and how many other accounts your day-to-day person carries.
How to vet a candidate
Ask to be added to two of their clients' lists and read what arrives for a fortnight. That single request tells you more than any deck: you will see the sending cadence, the writing quality, whether the flows fire correctly and whether the store's voice survives the agency. Ask for a flow audit before a contract, even a paid one, and see whether the findings are specific to your store. Ask which platforms they build in daily rather than which they list, since depth in one is worth more than shallow familiarity with five. Then ask for two references and put one question to them: what happened after the initial build, when the work became maintenance.
Questions people ask about email marketing agency for ecommerce
How much of ecommerce revenue should email produce?
It varies enormously by category, list size and purchase frequency, and any agency quoting a universal share is quoting a marketing slogan. Consumables and repeat-purchase categories see far more from email than considered one-off purchases. Establish your own baseline first, then judge the agency on movement against it rather than against someone else's benchmark.
Should the agency also handle SMS?
Often yes, because the two channels share the same audience and should not compete for the same moment. Consent rules for SMS are stricter than for email, so check that the agency can describe them without hedging. If it treats SMS as another broadcast channel rather than a permissioned one, keep it away from your phone list.
Who owns the account and the list?
You do, always. Your email platform account should be in your company's name with the agency added as a user you can remove. If an agency proposes sending through its own account or its own domain, decline: you would be renting your customer relationships, and recovering them at the end of the contract would be slow at best.
How long until flows pay for themselves?
Flows usually show a measurable effect within a few weeks of going live because they fire against existing traffic immediately. Campaign programs take longer to judge, since you need enough sends to separate signal from seasonality. A fair first review point is the end of month three, with flow performance and deliverability metrics both on the table.