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Email Service Provider (ESP)

Funny illustration glossary
Because Gmail wasn’t meant for sending 10,000 emails at once.

An email service provider (ESP) is a platform that helps businesses send, manage, and optimize email campaigns. These services go beyond a basic email inbox by offering automation, segmentation, analytics, and design tools to improve customer engagement and marketing performance. Whether you’re sending newsletters, promotional emails, or automated sequences, an ESP makes it easy to reach your audience at scale.

Why can’t you just use Gmail for email marketing?

Sure, you can send a few emails from your regular inbox, but mass email marketing without an ESP is a nightmare. ESPs streamline the entire process, ensuring emails reach the right people at the right time - without getting flagged as spam.

  • Bulk email sending – ESPs can send thousands (or millions) of emails at once.
  • Automation & personalization – Trigger emails based on user actions (like abandoned carts or sign-ups).
  • Analytics & tracking – Know who opened, clicked, and converted.
  • Spam compliance – ESPs handle unsubscribe links and legal requirements.

What’s the difference between an ESP and a regular email provider like Gmail?

Gmail is great for personal use, but it’s not built for email marketing. ESPs, on the other hand, are designed for:

  • Bulk email sending – Gmail limits you to 500 recipients per day, while ESPs can send millions.
  • Email automation – ESPs allow you to set up welcome sequences, drip campaigns, and more.
  • Advanced analytics – Track open rates, clicks, and conversions.
  • Better deliverability – ESPs optimize emails to avoid spam folders and ensure better inbox placement.

What features should I look for in an ESP?

Not all ESPs are created equal. The best ones offer:

  • Drag-and-drop email builders – No coding required!
  • List segmentation – Send targeted emails based on customer behavior.
  • A/B testing – Test different subject lines and content to see what works best.
  • Integrations – Connect with CRMs, ecommerce platforms, and social media tools.
  • Automation & workflows – Set up email sequences that run on autopilot.

What are the best ESPs for businesses?

The right ESP depends on your needs. Here are some of the most popular options:

  • Mailchimp – User-friendly and great for small businesses.
  • Klaviyo – Perfect for ecommerce brands looking for advanced segmentation.
  • ConvertKit – Designed for content creators and bloggers.
  • HubSpot – A powerful CRM with built-in email marketing features.
  • ActiveCampaign – Best for automation-heavy email marketing.

How do ESPs help with email deliverability?

Nothing is worse than crafting the perfect email - only for it to land in spam. ESPs improve email deliverability by:

  • Authenticating emails – Using SPF, DKIM, and DMARC to verify legitimacy.
  • Managing bounce rates – Automatically removing invalid email addresses.
  • Monitoring sender reputation – Keeping your emails off blacklists.
  • Providing opt-out tools – Ensuring compliance with GDPR and CAN-SPAM laws.

Are free ESPs worth using?

Many ESPs offer free plans, but they usually have limitations on the number of emails you can send, branding on emails, or limited automation features. Free ESPs are great for beginners, but growing businesses often need to upgrade for advanced features and better performance.