Mailgun vs Zeffy

About

Mailgun is a transactional email API platform providing developer-friendly email sending, tracking, and deliverability infrastructure for applications — enabling developers to integrate email sending via REST API or SMTP relay for transactional emails (password resets, order confirmations, notifications, alerts) at high volume with delivery analytics and bounce handling. Acquired by Sinch (the Swedish cloud communications company), Mailgun processes 450 billion+ emails annually for 150,000+ businesses.\n\nMailgun's API-first approach targets developers who need to send emails programmatically from their applications — the platform provides deliverability infrastructure (dedicated IP management, ISP relationship management, feedback loop processing), email validation (verifying email addresses before sending), and routing and tracking (open/click tracking, bounce categorization). The Mailgun dashboard provides senders with real-time visibility into delivery rates, bounce rates, spam complaints, and engagement metrics. The platform achieved 97.4% delivery rate compared to an 84.8% industry average, with 0.42% bounce rate.\n\nIn 2025, Mailgun operates as part of Sinch's email business alongside Mailjet and SparkPost (both also acquired by Sinch) — creating a combined email infrastructure offering that covers API email, marketing email, and high-volume email sending across different use cases and market segments. Mailgun competes with SendGrid (Twilio), Postmark (ActiveCampaign), and Amazon SES for transactional email API market share. During Black Friday/Cyber Monday 2024, Mailgun delivered 7.68 billion interactions at 95,000 messages per second peak, demonstrating the scale of infrastructure required for modern email delivery. The 2025 strategy focuses on deepening developer tooling, growing in the Sinch ecosystem alongside SMS and messaging products, and maintaining deliverability leadership as inbox providers continue tightening sender requirements.