The platforms, one by one
ActiveCampaign
Who it fits: full-service agencies that run client automation and also need a CRM to track their own prospects in the same account.
The Starter plan includes email marketing, marketing automation, a standard CRM and ecommerce integrations, which lets one team handle delivery and sales follow-up. For an agency running client work, Plus is the handoff point for standard segmentation and landing pages, while Pro adds advanced segmentation for accounts with more detailed audience rules. That tiering lets the operations team build journeys for a client and the account lead track the agency's own leads without a second tool.
Where it falls short: cost rises with the contact count, and each step up adds features you may not need for smaller clients. Agencies with many separate client lists should check how pricing applies across accounts before committing.
Price: Starter $15 a month at 1,000 contacts, Plus $49, Pro $79 and Enterprise $145 at the same contact baseline. Monthly and annual billing show the same monthly figure. Free trial available. See the ActiveCampaign pricing page.
Klaviyo
Who it fits: agencies whose clients are mainly ecommerce brands and need retention flows, abandoned-cart work and purchase-based segmentation.
Klaviyo's email plan is priced by active profiles, from $20 a month for 500 profiles to $400 a month for 25,000. A free plan covers 250 profiles and 500 email sends a month, which is enough to build and test flows for a pilot client.
Where it falls short: it is built around ecommerce data, so it is a weaker fit for B2B or non-retail clients. SMS is priced separately, and the pricing page does not list a fixed amount for the Email plus SMS tiers, so quote those on request.
Price: Email plan from $20 a month for 500 profiles (monthly), $30 for 1,000, $60 for 2,500, $100 for 5,000, $150 for 10,000 and $400 for 25,000. See the Klaviyo pricing page.
Mailchimp
Who it fits: agencies with small client lists, or clients who already run Mailchimp and do not want to retrain.
The free plan allows up to 250 contacts and 500 sends a month, with a maximum of 250 sends a day. That is enough for a pilot or a small newsletter. The Standard plan starts at $20 a month for a 500-contact list and includes up to 6,000 emails a month at that size.
Where it falls short: per-contact pricing steps up quickly. The 5,001 to 10,000 contact band is $135 a month and the 10,001 to 15,000 band is $230 a month, so larger client lists become expensive faster than on some other platforms in this guide.
Price: Free to 250 contacts; Standard $20 a month at 500 contacts; $100 a month for 2,501 to 5,000 contacts; $135 a month for 5,001 to 10,000; $230 a month for 10,001 to 15,000. See the Mailchimp pricing page.
Drip
Who it fits: ecommerce agencies managing mid-sized client lists where automation and segmentation matter more than the widest feature set.
Drip charges by people in bands, with unlimited email sends on the listed tiers. Each tier adds up to 50 workflows and dynamic segments, and the higher tiers add chat and email support. The pricing page also lists a free migration and personalized onboarding on the largest band.
Where it falls short: there is no ongoing free plan, only a 14-day trial with no credit card needed. The bands are fixed, so a client who grows just past a band pays the next step at once.
Price: $39 a month for 1 to 2,500 people; $49 for 2,501 to 3,000; $89 for 4,501 to 5,000; $154 for 9,001 to 10,000; $369 for 22,501 to 25,000. See the Drip pricing page.
Customer.io
Who it fits: agencies whose SaaS clients need lifecycle messages triggered by product events, such as onboarding steps, usage milestones or account changes.
The Essentials plan is $100 a month and includes the visual workflow builder, email and community support and basic data integrations. Profile-based tiers run from $145 a month at 10,000 profiles, and Premium offers custom profile volume with premium support. Eligible early-stage companies that have raised under $10 million can receive 12 months free through the Startup Program.
Where it falls short: it is not a good fit for a simple newsletter client, and the cost grows fast with profile count. It also needs someone who can map product events, so a smaller team may find it heavy.
Price: Essentials from $100 a month; Essentials at 10k profiles $145, 20k $235, 30k $325, 40k $415 and 50k or more $505 and up, all billed monthly. Premium is custom. See the Customer.io pricing page.
Campaign Monitor
Who it fits: agencies whose work is mainly brand campaigns and where the look of each send matters to the client.
Campaign Monitor's pricing is banded by contact count. The Lite plan is $13 a month on monthly billing or $11.70 a month billed annually, and includes five times the subscriber count in emails a month. Essentials, at $31 a month or $27.90 billed annually, includes unlimited email sends. Premier, at $171 a month or $153.90 billed annually, adds premier support, including phone support.
Where it falls short: there is no ongoing free plan, only a 30-day trial that covers 500 contacts and a 500-email limit. The bands also mean client growth moves the price up in steps. Check the feature list on the pricing page for any agency-specific features you need, since those are not covered by the plan prices above.
Price: Lite $13 a month ($11.70 billed annually); Essentials $31 ($27.90); Premier $171 ($153.90), all on a 500-contact band. See the Campaign Monitor pricing page.
Brevo
Who it fits: agencies with many small clients who need a low fixed cost and can work with monthly email volume bands.
The free plan allows 300 email sends a day and storage for up to 100,000 contacts, which makes it useful for trials and very small accounts. The Starter plan is $9 a month for 5,000 emails a month with no daily sending limit, and Standard is $18 a month at the same volume with automation, A/B testing and advanced reports.
Where it falls short: plans are priced by monthly sends, so a client that mails often moves into a higher band. The top Professional plan is $499 a month for 150,000 to 10 million monthly sends.
Price: Free; Starter $9 a month from 5,000 emails; Standard $18 a month from 5,000 emails; Professional $499 a month for 150,000 to 10 million sends. See the Brevo pricing page.
MailerLite
Who it fits: small client lists where budget is the first concern and the work is mostly newsletters and simple automations.
The free plan includes up to 250 subscribers and 2,500 emails a month. Paid plans start at the 500-subscriber tier: Comfort is $12 a month on monthly billing or $10.80 billed annually, and includes ten times the subscriber count in monthly emails. Power is $25 a month or $22.50 billed annually with unlimited monthly emails.
Where it falls short: the paid tiers start at 500 subscribers, so a client between 250 and 500 subscribers has to pay the lowest paid price even with a small list. Advanced reporting and deep segmentation are limited compared with the larger platforms.
Price: Free up to 250 subscribers and 2,500 emails a month; Comfort $12 a month ($10.80 billed annually); Power $25 a month ($22.50 billed annually). See the MailerLite pricing page.
Moosend
Who it fits: budget-conscious agencies that want real automation on each client account without paying for a larger platform.
Moosend's Pro plan is priced by contact count. At 500 contacts it is $9 a month on monthly billing or $7 a month billed annually. Email credit packs are sold separately, at 350,000 credits for $350 and 500,000 credits for $500 on the monthly listing.
Where it falls short: an agency cannot keep a client account on a permanent free tier; the entry route is a 30-day trial that does not require a credit card. Costs rise steeply past 25,000 contacts, and the contact tiers are fixed steps that can change the margin on a retainer when a client's list crosses a boundary.
Price: Pro at 500 contacts $9 a month ($7 billed annually); 1,000 contacts $16 ($13); 5,000 contacts $48 ($38); 10,000 contacts $88 ($70); 25,000 contacts $160 ($128). See the Moosend pricing page.
Kit
Who it fits: agencies with creator and newsletter clients who need landing pages, forms and broadcasts more than complex lifecycle automation.
The free plan covers up to 10,000 subscribers and includes unlimited landing pages and forms, unlimited email broadcasts, tagging and segmentation, and the ability to sell digital products and subscriptions. Visual Automations and email sequences start on the paid Creator plan at $33 a month billed annually.
Where it falls short: automations are not in the free plan, so a client who needs a welcome series from day one pays for Creator. The product is aimed at creators, so ecommerce or B2B clients may need a different tool.
Price: Kit has a free agency-friendly starting point up to 10,000 subscribers; Creator is $33 a month billed annually and Pro is $66 a month billed annually. Paid plans include a 14-day free trial. See the Kit pricing page.
GetResponse
Who it fits: agencies that run coaching, course or webinar clients where funnels, landing pages and events sit in one place.
Starter, at $19 a month monthly or $15.58 billed annually, includes unlimited monthly sends, a welcome series, one automation workflow, landing pages and signup forms. Marketer, at $59 monthly or $48.38 billed annually, adds unlimited workflows, advanced audience segmentation, abandoned-cart recovery and sales funnels. Creator, at $69 monthly or $56.58 billed annually, adds webinars, a website builder and a course creator.
Where it falls short: there is no ongoing free plan, only a free trial. Most of the useful funnel and webinar features sit above the Starter tier, so a client that needs them pays more.
Price: Starter $19 a month ($15.58 billed annually); Marketer $59 ($48.38); Creator $69 ($56.58). See the GetResponse pricing page.
AWeber and Constant Contact
Who they fit: small-business clients who prefer a simple setup and a known vendor. AWeber's Lite plan is $15 a month for 500 subscribers and 5,000 emails a month, and Plus is $30 a month for 500 subscribers and 6,000 emails a month. Constant Contact's Lite plan is $12 a month ($10.20 billed annually), Standard is $35 a month ($29.75 billed annually) and Premium is $80 a month ($68 billed annually) with 500 SMS a month.
Where they fall short: AWeber has a 14-day trial and no ongoing free plan. Constant Contact has a free trial with no credit card needed and no free plan. Automation depth is more limited than the operator platforms above.
Prices: AWeber pricing and Constant Contact pricing.