8 Best Email Marketing Software for Agencies in 2026

ActiveCampaign suits an agency that runs email and client records in one place. Starter starts at $15 a month billed annually, or $19 a month on monthly billing, for 1,000 contacts, and it adds a CRM, lead scoring and site tracking next to the email tools. The deep automation logic, with conditional paths and split testing, lets an agency build a different journey for each client without a second system.

The catch is the automation limit and the seat math. Each Starter automation stops at five actions, so a welcome series plus a cart recovery flow plus a win-back flow quickly needs Plus at $49 a month. There is also no free plan, only a 14-day trial, and each client account is billed on its own contact count. An agency with many small clients should price the whole book, not one account.

Brevo is the cheapest way for an agency to run email for several clients. Starter costs $9 a month for 5,000 emails, and because Brevo charges by emails sent rather than contacts stored, a client with a large list emailed twice a month costs less here than on contact-priced tools. The same account covers SMS, WhatsApp and a basic CRM, so an agency can offer more than one channel per client.

The catch is the thin entry tier and the missing white-label option. Automation and A/B testing only arrive on Standard at $18 a month, and the Brevo logo stays on Starter emails unless you pay for removal. There is no white-label client portal, so an agency that wants its own brand on every report will need a higher tier or a different tool.

Campaign Monitor is built for agencies that manage several brands. The template builder can pull a brand's colors and logo from a website URL, and higher tiers add template management and multi-brand, multi-team controls that keep each client's brand rules separate. Lite starts at $13 a month for 500 contacts, or $11.70 a month billed annually, with 2,500 sends a month.

The catch is the send cap and the missing free plan. Lite allows only five emails per subscriber per month, so a client that sends weekly to a 500-contact list will hit the limit, and there is no free plan, only a 30-day trial. Essentials at $27.90 a month billed annually adds unlimited sends, so an agency should price that tier for active clients.

Mailchimp suits an agency whose clients run on many different apps. It links to more than 300 tools, including Shopify, WooCommerce, Square and QuickBooks, so each client's sales data can shape who gets which email. Essentials starts at $13 a month for up to 500 contacts, and the free plan covers 250 contacts and 500 emails a month.

The catch is the price curve across a whole client book. Costs climb steeply as each list grows, and Mailchimp counts unsubscribed contacts toward the bill, so a messy client list costs real money. The free plan has no automation, no scheduling and no A/B testing. An agency should also check the per-client reporting, since deep client reports sit on the higher tiers.

GetResponse suits an agency that sells more than email. Starter starts at $19 a month for 1,000 contacts and bundles email with landing pages, forms, a website builder and AI writing help, while higher tiers add webinars and a course creator. The free plan covers 500 contacts and 2,500 emails a month, and Starter includes three user seats, which helps a small agency team share one account.

The catch is the automation limit and the price. Starter allows only one custom automation workflow, so a welcome series plus a cart recovery flow needs Marketer at $59 a month. At $19 a month, Starter is one of the priciest entries here. An agency that only sends newsletters will get the same core job done for $9 a month on Brevo.

Drip suits an agency with ecommerce clients. Its automation builder triggers on what a shopper viewed, how often they bought and what they almost bought, and revenue attribution ties every campaign to purchases, which makes client reporting easy. Every plan includes the same features with unlimited email sends, so the $39 a month entry for up to 2,500 people buys the whole product.

The catch is the price across a whole client book. At $39 a month per client it is the priciest entry in this list, and there is no free plan, only a 14-day trial. The price also scales hard with list size, reaching $154 a month at 10,000 people. Drip suits an agency whose clients already earn from email, not an agency still proving the channel.

Klaviyo suits an agency with Shopify clients. Its native integration pulls orders, browse history and cart events into every account, and the flows, segments and reporting all run on that data. The free plan covers 250 active profiles and 500 emails a month, so a new client account can run welcome and abandoned-cart flows before paying, and the Email plan starts at $20 a month for 251 to 500 profiles.

The catch is the billing model across a client book. Klaviyo charges by active profiles, which includes browsers and cart abandoners who never gave an email address, and there is no annual discount on self-serve plans. An agency should price each client at the 10,000-profile tier, which runs $150 a month, before quoting a retainer.

Omnisend suits an agency with small store clients. The free plan covers 250 contacts and 500 emails a month with all features, including automation and segmentation, and Standard starts at $16 a month for 500 contacts with 6,000 emails. Pre-built abandoned-cart, welcome and browse-abandonment workflows are ready to switch on the day each client store connects.

The catch is the SMS change from May 2026. New subscribers can no longer buy SMS on Standard; SMS now needs the Pro plan at $59 a month. Standard is still the right tier for email-only clients, but an agency that promises email plus SMS in one bill should price Pro from the start.