Mailsec - 2026 Pricing, Features, Reviews & Alternatives

Mailsec is a cloud-based (SaaS) email security platform that helps organizations protect their domains through email authentication, DNS monitoring, and threat detection. It covers the full stack of email authentication standards, including DMARC, SPF, DKIM, MTA-STS, TLS reporting, BIMI, and S/MIME, alongside continuous DNS monitoring with change detection and syntax error identification. By enforcing strong authentication policies, Mailsec reduces exposure to phishing, spoofing, and domain impersonation attacks while improving email inbox placement and domain reputation.

Mailsec is structured across tiered subscription plans (Starter, Protector, Guardian, Sentinel), scaling from small businesses managing 2 domains and up to 12,000 messages per month, to large enterprises and managed service providers (MSPs) handling 15 or more domains and up to 2 million messages per month. MSPs are explicitly supported through multi-organization account management. Higher-tier plans (Guardian and Sentinel) include AI-powered anomaly detection and real-time alerts for proactive threat identification. The platform also provides SIEM and ticketing integrations, API access, automation capabilities, a transactional email API, spam challenger, and zero trust inbox protection.

Applicable across industries that depend on email communication and require compliance with DMARC and related authentication standards, Mailsec surfaces detailed DMARC and TLS reports, monitors for lookalike domains, enforces email encryption in transit via MTA-STS, and supports BIMI implementation for brand logo verification in email clients. Multi-user account management, multi-factor authentication (MFA), and SSO support address enterprise access control requirements.