how to compare ESPs

How to compare ESPs effectively is less about collecting feature matrices and more about scoring vendors against the jobs you will run every week. Pricing pages look comparable until contact definitions differ. Deliverability claims sound similar until authentication support and list practices diverge. This framework helps you evaluate email service providers with fewer surprises.

Step 1: Define the jobs to be done

Write the concrete outcomes you need in the next 12 months. Examples:

• Weekly newsletter plus a five-email onboarding sequence
• Ecommerce lifecycle flows with browse and purchase data
• Creator newsletter with paid upgrades and referrals
• Transactional product email alongside marketing campaigns
• Multi-brand agency sending with client separation

If the job is creator publishing, include Substack, Beehiiv, and Kit in the consideration set even though they are not classic ESPs. If the job is ecommerce lifecycle, Klaviyo rises. If the job is general SMB campaigns, Mailchimp, Brevo, Constant Contact, and Campaign Monitor are natural peers. If the job is automation-heavy nurturing, ActiveCampaign deserves a slot. If the job is enterprise orchestration, Braze and Iterable enter the shortlist.

Self-hosted options such as Listmonk, Keila, and Mautic belong in comparisons when control and unit economics dominate—paired with Amazon SES, Mailgun, SendGrid, or Postmark for delivery.

Step 2: Normalize pricing before you fall in love

Contact versus volume versus platform fees

Ask each vendor:

• What counts as a billable contact?
• Do inactive or unsubscribed contacts count?
• Are automations, A/B tests, and seating gated by plan?
• What happens at the next list-size threshold?
• Are SMS, landing pages, or support tiers extra?

Mailchimp-style contact pricing differs from Amazon SES volume pricing. Newsletter platforms like Beehiiv, Substack, and Kit may include monetization fees or plan limits that are not comparable one-to-one with ActiveCampaign tiers. Postmark pricing optimized for transactional mail should not be naively compared with Campaign Monitor campaign plans.

Build a spreadsheet with three scenarios: current size, 2x list, and 2x send frequency. The winner at today’s size may lose at next year’s size.

Hidden cost centers

Include migration labor, template rebuilds, app integrations, and deliverability warming. Moving off Klaviyo or Mailchimp can be smooth or painful depending on how proprietary your automations became. Leaving a self-hosted Mautic instance also has cost if institutional knowledge is thin.

Step 3: Evaluate deliverability as a system

No ESP can guarantee the inbox. Compare how vendors help you operate reputation:

• Domain authentication wizards and DMARC guidance
• Bounce and complaint handling defaults
• Dedicated IP options and warming support
• Engagement dashboards you will actually use
• Support quality when something goes wrong

Transactional specialists such as Postmark emphasize reliable infrastructure for expected messages. SendGrid, Mailgun, and Amazon SES provide flexible APIs with responsibility shared by your team. Marketing ESPs like Brevo, ActiveCampaign, and Mailchimp embed deliverability tools in campaign workflows. Enterprise platforms Braze and Iterable add governance for complex setups.

If you self-host Listmonk or Keila, score yourself honestly on ops maturity. The vendor comparison becomes partly an internal capability comparison.

Step 4: Score features that change weekly work

Creative and templates

Campaign Monitor and Mailchimp are often strong for design workflows. Klaviyo emphasizes commerce blocks. Beehiiv and Kit optimize for newsletter composition. Substack prioritizes simplicity. Ghost(Pro) ties email to site themes. Code-first teams may care more about clean HTML hosting on SendGrid or Listmonk than about drag-and-drop chrome.

Segmentation and automation

ActiveCampaign and Klaviyo typically outpace basic newsletter tools here. Constant Contact and Campaign Monitor cover many SMB journeys. Braze and Iterable are built for sophisticated multi-channel paths. Choose depth you will use—not depth that looks impressive in a demo.

Data and integrations

Map CRM, CMS, and commerce requirements. WordPress forms, Shopify events, and warehouse syncs change the shortlist. Brevo’s broader channel mix may reduce tool count for smaller teams. Amazon SES integrations assume engineering support.

Analytics

Decide whether you need cohort revenue attribution, simple open/click trends, or creator growth analytics. Beehiiv’s analytics priorities differ from Iterable’s enterprise reporting. Align metrics with decisions you actually make.

Step 5: Run a structured trial

Demos hide friction. For your top two or three finalists:

1. Recreate one real newsletter issue

2. Build one real automation or sequence

3. Connect one critical integration

4. Complete authentication on a test subdomain

5. Measure time-to-first-send with your actual team roles

Include a creator platform finalist if relevant—Beehiiv versus Kit versus an ESP like Mailchimp is a fair test when workflows differ. Include Postmark or SendGrid only for the transactional portion of the stack rather than forcing them to be your newsletter editor.

Step 6: Assess risk, support, and portability

Compare contract flexibility, data export quality, regional hosting, and compliance documentation. Agencies may prefer Campaign Monitor or Mailchimp ecosystems; regulated enterprises may lean toward Braze, Iterable, or carefully managed Amazon SES architectures. Open-source paths with Mautic, Listmonk, or Keila improve portability but increase ownership risk.

Ask for support SLAs that match your send schedule. A weekly newsletter can tolerate slower support than a transactional pipeline tied to checkout.

A simple scoring model

Weight categories to your context—for example:

• Pricing trajectory: 25%
• Deliverability operations: 25%
• Weekly workflow fit: 30%
• Integrations and data: 10%
• Support and portability: 10%

Score each vendor from 1–5. The math will not replace judgment, but it prevents charismatic demos from erasing cost cliffs.

Involve the people who will actually build issues and journeys—not only the buyer who attends vendor webinars. An editor who thrives in Beehiiv may struggle in a MAP canvas; a lifecycle marketer who loves Klaviyo may find Substack too limited. Capture those qualitative notes beside the numeric scores so the final choice reflects lived workflow.

When you compare ESPs this way—pricing, deliverability, and features as an operating system—you shortlist tools that fit how you publish, not just how vendors market themselves. Whether you land on Mailchimp, Klaviyo, ActiveCampaign, Brevo, Beehiiv, Kit, Substack, Ghost(Pro), Campaign Monitor, Constant Contact, SendGrid, Mailgun, Postmark, Amazon SES, Listmonk, Keila, Mautic, Braze, or Iterable, the winning choice is the one your team can run excellently at next year’s scale.

Further reading

• Explore the email service provider directory for vendor profiles.
• Follow the ESP selection guide for deeper evaluation worksheets.
• Use the ESP comparison hub to review side-by-side differences.