Fortinet FortiMail Email Security vs Mimecast Advanced Email Security: Side-by-Side Comparison (2026)

Short answer

Mid-market and enterprise teams defending Microsoft 365 or Google Workspace environments should prioritize FortiMail for its pattern-based anomaly detection, which catches business email compromise and account takeover attempts that signature-only solutions miss. The platform's dual protection via gateway and API, combined with real-time FortiGuard threat intelligence, covers both inbound phishing and outbound data exfiltration, scoring strong on NIST DE.CM continuous monitoring. Skip this if your organization needs deep Slack or third-party collaboration app coverage; FortiMail's strength is email-specific, not broader communication channels. Mid-market and enterprise security teams defending Microsoft 365 or Google Workspace should prioritize Mimecast Advanced Email Security for its social graphing and computer vision capabilities, which catch impersonation and BEC attacks that signature-based filters routinely miss. The platform scores across NIST's Detect and Prevention functions with sandboxing, on-click URL protection, and contextual banners that work together to stop threats after inbox delivery. Skip this if your organization needs email security bundled with broader cloud access control or data loss prevention; Mimecast stays focused on threat detection rather than competing with DLP platforms.