Email service providers

An Email Service Provider (ESP) is a platform that enables businesses to send email at scale, whether transactional (like password resets and receipts) or marketing (like newsletters and promotions). ESPs handle the infrastructure and advice on compliance and deliverability concerns so that senders can focus on content and strategy. 

There are two main types of ESPs: 

• API-driven ESPs (e.g., Mailgun): Focused on developers and product teams, providing email-sending capabilities via HTTP APIs or SMTP relay. Ideal for transactional and triggered mail from apps or services. 
• Marketing-focused ESPs (e.g., Mailjet): Offer visual editors, contact list management, and campaign-building tools. Tailored for marketers who manage promotional sends and audience segmentation. 

Common ESP features include: 

• Sending infrastructure and IP management 
• Authentication support (SPF, DKIM, DMARC) 
• List and contact management 
• Email templates and personalization tools 
• Analytics and event tracking (opens, clicks, bounces, conversions) 
• Compliance tooling and spam protection 

Mailgun provides both types of ESP functionality across its product ecosystem.