Best Email Security Tools

The email security platforms worth knowing in 2026, compared on threat detection, deployment and integrations. Listed neutrally, with no editorial scoring or rankings.

6 tools listed|2026|No editorial scoring|context: Proofpoint|Part of the Email Security guide

What this shortlist looks at

Threat detection

Depth of phishing, BEC, malware and zero-day detection, and whether it relies on signatures, behavioural analysis, or both.

Deployment and integration

Native fit with Microsoft 365 or Google Workspace, API-based versus gateway deployment, and ease of setup.

Reporting and compliance

Data loss prevention, archiving, and audit or compliance support built into the platform.

Pricing model

Per-user subscription cost at scale, and whether the platform is priced standalone or bundled with a wider suite.

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Paid placement

Paid placements, shown separately from the editorial shortlist below and not ranked among it.

Acronis Email Security

Featured

Acronis Cyber Protect Cloud with Acronis Email Security protects Microsoft 365, Google Workspace, and other mailboxes against phishing, BEC, account takeover, malware, and zero-day threats, integrated with backup, endpoint protection, and DLP.

Pricing: Subscription, add-on to Acronis Cyber Protect Cloud

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Tools listed here

Abnormal Security

Best for AI-driven behavioural detection

An AI-native platform built around behavioural detection rather than signatures, aimed at social engineering and BEC attacks that slip past traditional gateways. The clearest modern challenger in the category.

AI-powered email security platform specializing in behavioral detection of social engineering attacks

View listingAbnormal Security alternatives

Barracuda Email Security

Best value for small-to-mid-market

Email threat protection available as a gateway appliance or cloud service, positioned as a lower-cost alternative to Proofpoint and Mimecast for smaller organisations.

Email threat protection platform available as gateway appliance or cloud service

View listingBarracuda Email Security alternatives

IRONSCALES

Best for automated phishing response with built-in training

AI-powered anti-phishing with crowdsourced threat intelligence, combined with integrated security awareness training and phishing simulation. A strong fit for mid-market teams that want detection and user training in one platform.

AI-powered anti-phishing platform with crowdsourced threat intelligence

View listingIRONSCALES alternatives

Microsoft Defender for Office 365

Best for Microsoft 365-native protection

Microsoft's own email security for Microsoft 365, with native XDR integration. Bundled into E5 licensing, making it the default for organisations already standardised on Microsoft 365.

Microsoft's native email security for Microsoft 365 with XDR integration

View listingMicrosoft Defender for Office 365 alternatives

Mimecast

Best for unified email security, archiving and continuity

A cloud email security platform that pairs threat protection with archiving and continuity in one product, with strong API integrations. A comparable-scale alternative to Proofpoint for mid-to-large enterprises.

Cloud email security platform with threat protection, archiving, and continuity

View listingMimecast alternatives

Proofpoint

Best for enterprise threat protection and compliance

The long-established enterprise incumbent, combining advanced threat protection with compliance and data loss prevention. The vendor most large organisations already evaluate first.

Enterprise email security platform for advanced threat protection, compliance, and data loss prevention

View listingProofpoint alternatives

For the full category walkthrough with every tool compared, see the Email Security guide.

Frequently Asked Questions

Email security software protects inboxes against phishing, business email compromise, malware, account takeover, and other email-borne threats, typically by analysing inbound (and sometimes outbound) mail traffic for known and unknown attack patterns before it reaches the end user.

Weigh detection depth against your actual threat profile (commodity phishing versus targeted BEC), how well it integrates with your existing Microsoft 365 or Google Workspace deployment, whether you need built-in DLP or archiving, and total cost per user at your organisation's scale.

Many organisations layer a third-party tool on top of Defender's native protection for deeper content analysis, faster verdicts, or capabilities Defender doesn't cover natively, such as integrated backup or advanced anti-evasion. Whether it's worth the added cost depends on your threat profile and existing stack.