Best Email Marketing Platforms for Agencies Managing Multiple Clients

For an agency running email for several clients, Campaign Monitor is the strongest fit: it is the only platform in this roundup whose standard pricing page lists client sub-accounts, private labeling, and a billing system that charges each client with your markup added. If margin matters more than client-facing polish, Moosend is the budget pick at about $48 a month per 5,000-contact client. Klaviyo is the right home for ecommerce clients, and Mailchimp is fine when the client already owns the account.

Prices below were read on vendor pricing pages on 2026-10-16, except where a vendor's price slider would not load and a dated third-party source is cited instead. Nobody at LogicBalls ran client campaigns in these tools for this roundup.

Key Takeaways

• Campaign Monitor bills each client separately and lets you add a markup. Its pricing page lists "Set up multiple sub-accounts under a main administrative account" and "Add a markup to the base price and let our billing system handle everything on your behalf" (Campaign Monitor pricing, retrieved 2026-10-16).
• At 5,000 contacts, Campaign Monitor Essentials is $117 a month per client, Lite $75 and Premier $203 (same source). For 10 clients on Essentials that is $1,170 a month at list price, before your markup.
• Mailchimp has no sub-accounts; agencies connect to client-owned accounts through its free Mailchimp & Co program, up to 35 access requests a day (Mailchimp help, retrieved 2026-10-16).
• ActiveCampaign discounts resold accounts by volume: 25% off from two active accounts, rising to 55% at 100 (ActiveCampaign Agency Partner Agreement, retrieved 2026-10-16).
• Brevo puts multi-account management on Enterprise only: "Manage multiple business units & brands under one master account" (Brevo pricing, retrieved 2026-10-16).

What agencies need that brands don't

A brand needs one list, one sender, one invoice. An agency needs the opposite on every axis, and generic "best email tool" lists ignore all of it:

1. Separation between clients. Each client's contacts, sending domain, templates and reports must be isolated. Mixing two clients' lists in one account creates consent and deliverability problems that are hard to unwind.
2. One login for your team. Switching between 10 client accounts with 10 passwords does not scale and fails every security review.
3. Permissions per client. A client's marketing lead should see their own reports and maybe approve campaigns, and nothing else.
4. Billing you can mark up or pass through. Either the client pays the platform directly (simple, no margin) or you pay and rebill (margin, but cash-flow risk). The best agency tools do the rebilling for you.
5. White-labeling. Some agencies want clients to log in to "their" platform, not the vendor's.

Score each tool below against those five, not against feature counts.

Client sub-accounts and permissions

Sources are cited in each section below.

Campaign Monitor: built for agencies

Campaign Monitor is the only platform here whose public pricing page has an "Agency features" section. It lists a tiered account setup ("multiple sub-accounts under a main administrative account"), a dashboard "for monitoring performance across your client accounts", user roles and permissions per client, private labeling ("remove all Campaign Monitor branding from the app and replace it with your own"), markup options, in-app billing management, contract and pay-as-you-go billing per client, template and automation sharing across sub-accounts, unique API keys per sub-account, and charging in local currency (Campaign Monitor pricing, retrieved 2026-10-16).

The mechanics are documented in its API: billing is set per client, with a ClientPays option and a markup percentage that "will apply to the base prices at each pricing tier" (Campaign Monitor API, clients, retrieved 2026-10-16). In plain terms, each client sits on its own plan at its own contact tier, the client can pay by card, and Campaign Monitor adds your margin and collects it. The pricing page does not make clear which plan each agency feature requires, so confirm private labeling and markup for your plan with sales before you promise them to a client.

Pricing at 2,501 to 5,000 contacts (monthly, USD, retrieved 2026-10-16): Lite $75 (25,000 sends a month), Essentials $117 (unlimited sends), Premier $203. Annual plans get a 10% discount and nonprofits 15% (Campaign Monitor pricing).

Not for: agencies whose clients are mostly Shopify stores that need deep product-catalog flows, and very price-sensitive agencies where every client is under 5,000 contacts and the client is paying.

Mailchimp: the default, with caveats

Mailchimp is the platform your clients most likely already use. It has no sub-account structure. Instead, you join Mailchimp & Co (free) and request access to each client's account; you can then "access and switch between your clients' accounts without sharing login information", request up to 35 client accounts a day, and requests expire after 7 days if the client does not approve (Mailchimp help, connect client accounts, retrieved 2026-10-16). The partner program page lists tools for managing multiple clients and commission, without publishing rates (Mailchimp partners, retrieved 2026-10-16).

Three caveats for agencies:

• Seats are capped. Essentials allows 3 seats and Standard 5; Premium is unlimited (Mailchimp help, pricing plans, retrieved 2026-10-16). Your team plus the client's team can hit 5 quickly.
• Unsubscribes count. "Subscribed, unsubscribed, and non-subscribed contacts are included in your contact count" (same source). A client with 5,000 subscribers and 1,500 unsubscribes is billed on the 6,500 tier unless someone archives contacts.
• Price at 5,000 contacts. Mailchimp's price slider did not load in our retrieval; the page showed Essentials from $13 and Standard from $20 at 500 contacts. GroupMail's March 2026 breakdown lists $75 a month for Essentials and $100 for Standard at 5,000 contacts (GroupMail, retrieved 2026-10-16). Check the slider before quoting a client.

Not for: agencies that want to own the platform relationship, rebill with margin, or white-label.

Klaviyo: ecommerce clients

Klaviyo is where Shopify and other ecommerce clients usually end up. For agencies, the useful feature is multi-account access: one login can switch between accounts, with a different role in each, for example Admin in one and a restricted role in another (Klaviyo help, multiple accounts, retrieved 2026-10-16). Each client is its own account and its own bill.

Klaviyo bills on active profiles, defined on its pricing page as "contacts who may receive marketing emails", and the free plan covers up to 250 profiles and 500 emails a month (Klaviyo pricing, retrieved 2026-10-16). Paid prices are behind a slider that did not load for us; Charle's May 2026 table puts the Email plan at $100 a month for 3,501 to 5,000 profiles (Charle, retrieved 2026-10-16).

Not for: B2B, nonprofit or newsletter clients with no store data. You pay for ecommerce depth they will not use.

Moosend: budget multi-client pick

Moosend is the cheapest per client of the tools here. Its pricing page shows the Pro plan with monthly, six-month and annual billing, "Save 20%" on annual, and 5 team members on Pro (Moosend pricing, retrieved 2026-10-16). The slider price did not render in our retrieval; EmailVendorSelection's August 2026 breakdown lists Pro at $48 a month for 5,000 contacts on monthly billing, $41 on six-month prepay and $38 on annual, with unlimited sends (EmailVendorSelection, retrieved 2026-10-16).

What Moosend does not list on its pricing page is any sub-account, client dashboard or white-label feature. Its agency program is a referral model instead: "Recurring commissions up to 30%", with the option to give clients "10% off" and adjust your commission to 20% (Moosend agency program, retrieved 2026-10-16). So the agency workflow is one Moosend account per client, the client pays, and you earn a recurring cut. Our Moosend review covers the product itself.

Not for: agencies that need one dashboard across clients or want clients to see a branded platform.

Brevo and ActiveCampaign

Brevo

Brevo prices by emails sent, not by contacts. Its pricing page lists Starter at $9 a month "From 5,000 emails per month", Standard at $18, Professional at $499 (from 150,000 emails, 10 seats) and Enterprise on quote (Brevo pricing, retrieved 2026-10-16). Those are entry prices: a 5,000-contact client emailed weekly sends about 20,000 emails a month, and the price at that volume sits behind a slider we could not read. Multi-account management, "Manage multiple business units & brands under one master account", is listed under Enterprise only (same source).

For an agency, that makes Brevo a good per-client choice for low-frequency senders, since contacts are not what you pay for, but not an agency platform until you reach Enterprise. More in our Brevo review.

ActiveCampaign

ActiveCampaign has the most explicit reseller economics. Under its Agency Partner Agreement, the first active resold account is full price, then "At least two active accounts, discounted at 25% off the monthly fee", 35% from 25 accounts, 45% from 50 and 55% from 100. ActiveCampaign adds that it "may revise or change our pricing and discount structure at any time" (ActiveCampaign Agency Partner Agreement, retrieved 2026-10-16). In this model the agency is billed and sets its own client price, so the discount is your margin.

The pricing page lists 1 user on Starter and Plus, 3 on Pro and 5 on Enterprise, but its prices did not load in our retrieval (ActiveCampaign pricing, retrieved 2026-10-16), so we have left it out of the cost table.

Kit

Kit (formerly ConvertKit) is worth knowing for creator clients: its free Newsletter plan covers up to 10,000 subscribers with 1 user, and Creator is $33 a month at 1,000 subscribers (Kit pricing, retrieved 2026-10-16). It lists no agency or multi-client features.

Cost for 10 clients at 5,000 contacts each

Here is list price for 10 separate client accounts at 5,000 contacts each, per month, before any agency discount or markup.

How to read it:

• If clients pay the platform directly, the cheapest row wins and the agency features do not matter much. Moosend at $380 to $480 for all 10 is hard to beat, plus up to 30% back in commission.
• If you rebill, the question is margin and admin time. A 20% markup on Campaign Monitor Essentials turns $1,170 into $1,404 billed to clients, with Campaign Monitor collecting, which is $234 a month you did not have to invoice for.
• If you resell ActiveCampaign, the 25% discount from the second account is the margin, but you carry the billing and the bad-debt risk.
• Ten different plans is normal. Real clients sit at different tiers, so build this table with your actual list sizes.

For the AI features each of these tools now ships, see our roundup of AI tools for email marketing.

Frequently Asked Questions

Which email platform has sub-accounts for agencies?

Campaign Monitor lists multiple sub-accounts under one admin account on its standard pricing page, along with per-client billing and markup. Brevo offers multi-account management on its Enterprise plan. Mailchimp, Klaviyo and Moosend use separate accounts per client instead, with account switching for Mailchimp and Klaviyo.

Can I white-label an email marketing platform for clients?

Of the tools here, Campaign Monitor is the one whose pricing page lists private labeling: removing Campaign Monitor branding from the app and replacing it with your own, and its agency page mentions adding your logo, colors and domain. The other platforms reviewed do not list app white-labeling on their pricing pages.

Is it cheaper to put all clients in one account?

Sometimes on paper, but it is risky. One shared account mixes consent records, sender reputation and data access across clients, and makes handing a client their list back difficult. Separate accounts or sub-accounts per client are the safer structure, and most platforms price per account anyway.

How do agencies make money on email platforms?

Three ways: a markup on the platform fee (Campaign Monitor's billing system adds it for you), a reseller discount you keep (ActiveCampaign's agency program, from 25% off), or referral commission while the client pays the vendor (Moosend lists up to 30% recurring). Many agencies also simply charge for management time and let the client pay the platform.

What is the cheapest email platform for multiple clients?

At 5,000 contacts per client, Moosend Pro was the lowest list price we found: $48 a month per client on monthly billing or $38 on annual, per EmailVendorSelection's August 2026 figures. Kit's free plan covers up to 10,000 subscribers but allows only one user and lists no multi-client features.

How this guide was researched

We read the pricing pages of Campaign Monitor, Mailchimp, Klaviyo, Moosend, Brevo, ActiveCampaign and Kit, plus Campaign Monitor's client API documentation, Mailchimp's and Klaviyo's help articles on multiple accounts, and the Moosend and ActiveCampaign agency program terms, on 2026-10-16. Where a price slider did not load, we used a dated third-party pricing breakdown and named it. Tools were compared from documentation, pricing and public information, not hands-on testing. LogicBalls may earn a commission from some links in this post, which does not change the order or the verdicts.