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ESP Email Deliverability Insights

Compare inbox placement benchmarks, authentication requirements, and deliverability features across top email service providers

Each ESP has different approaches to shared IPs, DMARC alignment, and deliverability tooling. See how they compare — and which one fits your sending program.

ActiveCampaign

A

Customer experience automation platform

Primary inbox rate20%
Avg spam rate13.8%
TypeMarketing

Amazon SES

B

Amazon's cloud-based email sending service

Primary inbox rate19%
Avg spam rate16.2%
TypeTransactional

Braze

A

Customer engagement platform for enterprise brands

Primary inbox rate23%
Avg spam rate11.2%
TypeMarketing

Brevo

B

All-in-one marketing platform (formerly Sendinblue)

Primary inbox rate18%
Avg spam rate15.4%
TypeMarketing + Transactional

Campaign Monitor

B

Email marketing platform for small businesses and agencies

Primary inbox rate19%
Avg spam rate15.2%
TypeMarketing

Constant Contact

C

Email marketing and online tools for small businesses

Primary inbox rate17%
Avg spam rate16.5%
TypeMarketing

Drip

B

Email marketing and marketing automation for ecommerce

Primary inbox rate20%
Avg spam rate13.8%
TypeMarketing

HubSpot

A

CRM-native email marketing and automation

Primary inbox rate21%
Avg spam rate13.2%
TypeMarketing

Klaviyo

A

The ecommerce email and SMS platform

Primary inbox rate22%
Avg spam rate12.1%
TypeMarketing

Mailchimp

B

The all-in-one marketing platform for small businesses

Primary inbox rate18%
Avg spam rate14.8%
TypeMarketing

Mailgun

B

Email API for developers

Primary inbox rate19%
Avg spam rate17.3%
TypeTransactional

Omnisend

B

Email and SMS marketing automation for ecommerce

Primary inbox rate21%
Avg spam rate14.2%
TypeMarketing

Postmark

A

Transactional email built for speed and reliability

Primary inbox rate30%
Avg spam rate10.8%
TypeTransactional

SendGrid

A

Transactional and marketing email delivery at scale

Primary inbox rate20%
Avg spam rate13.5%
TypeMarketing + Transactional

Monitor your ESP's actual inbox placement

Benchmarks tell you industry averages. InboxEagle shows you your actual inbox placement rate across 20+ ISPs — including Gmail, Outlook, and Yahoo — updated after every send.

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The exact checklist used by 2,000+ email senders to diagnose and fix inbox placement issues — free.

  • Authentication setup (SPF, DKIM, DMARC)
  • Sender reputation signals to monitor
  • List hygiene benchmarks
  • Content & engagement red flags

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