Best 12 Email Security Solutions For Microsoft 365 (2026)

SpamTitan by TitanHQ is a cloud-based secure email gateway that provides comprehensive protection against spam, malware, ransomware, and phishing attacks. The platform is built on a powerful spam filtering engine with a catch rate of 99.99% and a false positive rate of 0.003%. SpamTitan provides strong threat protection against both inbound and outbound email threats, making it a strong solution for SMBs, enterprises, MSPs, and resellers.

SpamTitan Key Features

SpamTitan provides multi-layered threat protection for inbound emails, with spam filtering, powerful attachment sandboxing, and real-time URL scanning. The platform scans all inbound emails in real time, filtering out malicious content including links to phishing webpages and malicious attachments, preventing phishing and whaling attacks. Alongside inbound protection, admins can set up outbound data leak prevention rules to stop email data loss.

Policy configuration is straightforward, with the ability to set allow/deny lists, customize DLP rules, and apply policies by user, domain, and domain group. SpamTitan integrates easily with existing email systems and works well as an extra layer of security for Microsoft 365 accounts, providing enhanced threat protection and reporting. The service is backed by responsive and knowledgeable technical support.

Our Take

We think SpamTitan is an easy-to-manage email security solution for SMBs, enterprises, MSPs, and resellers that need comprehensive inbound threat protection without a complex deployment. The 99.99% catch rate and included sandboxing are strong value, and the outbound DLP capabilities add a layer of protection that many competing gateways lack. SpamTitan is also a strong option for education environments, where its cost-effective pricing model keeps it accessible.

IRONSCALES is an API-based email security platform that sits at the mailbox level inside Microsoft 365 or Google Workspace. It’s designed to catch phishing, BEC, and impersonation attacks missed by traditional gateways, and to reduce the time security teams spend on email incident response.

IRONSCALES Key Features

IRONSCALES connects to Microsoft 365 via the Graph API with no MX record changes, mail flow rules, or connector configuration required. The platform builds a baseline of normal email behavior and flags messages that deviate from it, catching impersonation and BEC attempts that pass technical checks. Crowdsourced threat intelligence from across the IRONSCALES customer base means a phishing campaign reported by one organization is blocked for all.

IRONSCALES uses AV engines and URL scanning to provide strong protection against malicious links and attachments. The platform also provides spam filtering and grey-mail protection, meaning it can be used as a standalone email security solution for Microsoft 365 without requiring a separate secure email gateway.

Our Take

We are impressed by IRONSCALES. The platform is constantly adding new features, like email spam filtering, encryption, and deepfake protection. The core of the product is the crowdsourced threat intelligence network, which gets stronger as the user base grows. IRONSCALES is a strong choice for organizations that want API-based protection with minimal deployment friction.

Material Security goes beyond email filtering to protect the full M365 or Google Workspace environment, including inbox data, documents, and account configuration. We think the data protection angle is genuinely different from most email security tools, which focus on inbound threats but ignore what attackers can access once they’re in.

Material Security Key Features

The platform scans historical mail for sensitive content like tax records and invoices, then puts MFA in front of it. Emails are automatically classified as sensitive and after a pre-determined period of time are hidden in the inbox until the user authenticates again. This means even a fully compromised account limits what an attacker can exfiltrate. API deployment runs in under 30 minutes with no MX record changes required.

What Customers Say

Customers say the automatic clustering of similar phishing messages saves investigation time, and the ‘report suspicious message’ button is one of the simpler features to roll out to end users. Based on customer feedback, the account takeover detection, which covers 2FA scams, password resets, and configuration drift, is a standout capability.

Our Take

We were impressed by the approach to protecting stored inbox data, which closes a gap most email security tools don’t attempt to address. If your concern is what happens after an account is compromised rather than just blocking initial delivery, Material Security deserves a look.

ESET Cloud Office Security extends ESET’s antimalware engine across the full Microsoft 365 stack, covering Exchange Online, Teams, OneDrive, and SharePoint. We think the cross-app coverage is the differentiator here. Most SMB email security tools protect the inbox and stop there, while ESET applies the same engine consistently across collaboration tools and file storage.

ESET Cloud Office Security Key Features

The same ESET antimalware engine applies consistently across email, files, and collaboration tools. We found the policy flexibility holds up well. You can configure threat protection at user, group, or organization level, which is useful for MSPs managing varied client environments. Native M365 integration deploys without MX record changes or mail flow rewrites, and the clean dashboard makes daily management manageable for smaller IT teams.

What Customers Say

Customers say deployment is one of the quicker setups in the category, with spam blocking kicking in within minutes of going live. The dashboard gets praise for being clean and daily management workload is low once the platform is tuned.

Our Take

We think ESET Cloud Office Security suits SMBs and midmarket organizations on M365 that want one platform covering email, files, and collaboration rather than buying separate tools for each. The management overhead is low once the platform is tuned.

Abnormal AI takes a behavioral approach to email security for Microsoft 365, building a communication baseline for every user and flagging messages that deviate from it. We think the behavioral baseline is the right approach for catching the BEC and social engineering attacks that signature-based filters routinely miss.

Abnormal AI Key Features

Abnormal analyzes communications against more than 45,000 threat indicators, learning normal patterns for each user so social engineering that passes technical checks still gets caught when it breaks behavioral norms. API deployment integrates with M365 in under an hour with no MX record changes. Auto-remediation forces logouts and resets credentials when accounts show signs of compromise, which closes the gap between detection and containment.

What Customers Say

Customers say the false positive rate is meaningfully lower than what they had with traditional gateways like Mimecast and Barracuda, and the API setup completes in under an hour. Greymail filtering and accurate detection reduce the time SOC teams spend on email triage.

Our Take

We were impressed by the auto-remediation, which forces logouts and resets credentials when accounts show signs of compromise. If your M365 environment has outgrown gateway filtering and you need a behavioral layer that catches what your SEG misses, Abnormal AI is a strong candidate.

Check Point Email Security, formerly Avanan, is an email and application security platform that sits within the Microsoft 365 environment rather than in front of it. Check Point acquired Avanan in August 2021 and has since integrated the platform into its broader Infinity security architecture. The platform protects organizations from phishing, malware, account compromise, and data loss across inbound, outbound, and internal email traffic.

Check Point Email Security Key Features

Because the platform sits within the Microsoft 365 environment, it can secure inbound, outbound, and internal emails, catching threats that perimeter-based gateways miss. Machine learning models analyze over 300 indicators of compromise, including sending time, location, and domain patterns, to identify zero-day phishing attacks and flag suspicious account behavior. The platform applies URL protection, sandboxing, DLP, and account takeover prevention across email, Outlook, Teams, and shared files from a single console. ML detection does solid work on subtle phishing attempts that signature filters and native M365 protections miss.

What Customers Say

Customers say threat detection runs quietly without slowing daily work, and the dashboard makes monitoring alerts and tracking file movement straightforward. Some users report the filtering can be too aggressive at times, sending legitimate emails into quarantine.

Our Take

We think Check Point Email Security fits midmarket and enterprise teams that want one platform covering email, Teams, and file sharing rather than separate tools per channel. Deployment as an app within the Microsoft 365 environment keeps the setup process manageable, and the cross-channel coverage is a genuine differentiator for organizations running collaboration tools beyond just email.

Cloudflare Email Security plugs into M365 via API and uses Cloudflare’s global threat intelligence network to catch phishing, BEC, and credential theft. We think the integration with the broader Cloudflare stack is the main reason to choose it. Standalone, it’s a capable product; paired with Cloudflare WAF, DNS, or SASE services, the shared threat intelligence compounds across products in ways that are hard to replicate with separate vendors.

Cloudflare Email Security Key Features

The platform uses ML models to analyze email content, intent, tone, sender relationships, and other attack signals. Post-delivery scanning catches threats that slip through initial filtering. Browser Isolation opens suspicious links in a sandboxed session, protecting endpoints from successful clicks. Native SIEM and SOAR integration feeds email signals directly into wider detection stacks, and threat intelligence draws on Cloudflare’s global network, one of the largest in the industry.

What Customers Say

Direct customer reviews for Cloudflare Email Security specifically are limited. From the wider Cloudflare platform, customers say the dashboard is approachable and deployment is one of the lighter lifts in the category.

Our Take

We think Cloudflare Email Security makes the most sense if your organization already runs WAF, DNS, or SASE services through Cloudflare. If you’re evaluating email security as a standalone purchase without existing Cloudflare investment, other vendors on this list offer more out-of-the-box depth.

Microsoft Defender for Office 365 is Microsoft’s native email and collaboration security platform for M365, formerly known as Office 365 Advanced Threat Protection before its rebrand in 2020. It covers Exchange Online, SharePoint, OneDrive, and Teams from a single console, and is included in some M365 subscriptions, including the Enterprise E5 tier, or available as a Defender Plan 1 or Plan 2 add-on.

Microsoft Defender for Office 365 Key Features

Safe Links rewrites URLs at click time and Safe Attachments detonates suspicious files in a sandbox before delivery. Anti-phishing protection uses machine learning and impersonation detection to block targeted attacks, though third-party vendors consistently outperform it on advanced phishing and BEC scenarios. Automated Investigation and Response, available in Plan 2, surfaces connected incidents and triggers remediation steps automatically, reducing analyst workload for SOC teams. The platform also extends protection to SharePoint, OneDrive, and Teams, which few third-party email security tools cover natively.

What Customers Say

Customers say AIR automation reduces manual remediation work for SOC teams, and Threat Explorer comes up repeatedly as a strong investigation aid. Some users report that configuration is spread across multiple Microsoft portals, making policy management more complex than expected.

Our Take

We think Microsoft Defender for Office 365 makes the most sense if your organization already runs E5 or has the Defender Plan 2 add-on. The integration depth with the rest of the Microsoft security stack is difficult to replicate with third-party tools. For organizations that rely heavily on Defender, adding a third-party layer like IRONSCALES or Abnormal AI on top is a common approach to address the gaps in advanced phishing detection.

Mimecast is a global leader in cloud-based email security, protecting over 42,000 customers worldwide, including many large enterprises. The platform delivers protection against phishing, malware, spam, business email compromise, and data breaches as a single subscription service. We think the bundled compliance tooling is what separates Mimecast from behavioral-only vendors. Archiving, encryption, and internal email protection are all included, which matters for organizations managing regulatory obligations alongside security.

Mimecast Key Features

Mimecast can be deployed as an MX-based gateway sitting in front of your Microsoft 365 tenant or via API for in-tenant scanning, giving organizations flexibility in how they route and inspect email traffic. The gateway deployment uses multi-layered threat detection to defend against spear-phishing, malware, viruses, spam, and data breaches. Internal Email Protect deploys inside the email perimeter to detect and remediate internal threats, and works alongside Mimecast’s Security Awareness Training to address sophisticated attacks like spear-phishing and email fraud. Mailbox-level compliant archiving provides e-discovery support, legal hold, and Microsoft 365 continuity in the event of an outage. Email encryption and DNS filtering are bundled in the platform. The March 2026 update added 350+ vendor integrations, addressing earlier criticism around SIEM and SOAR connectivity. Rule customization runs deep, supporting department-level filtering and custom phishing blocks.

What Customers Say

Customers say the rule-building interface is approachable, with options to fine-tune filtering by department or build custom blocks for emerging phishing patterns. Targeted Threat Protection earns repeated praise from enterprise admin teams for its accuracy on targeted attack campaigns.

Our Take

We think Mimecast works well for organizations that need email security and compliance tooling from a single vendor. The combination of MX gateway and in-tenant scanning, archiving, encryption, DNS filtering, and Security Awareness Training means Mimecast can serve as a complete Microsoft 365 email security solution without requiring multiple separate purchases. The March 2026 update adds 350+ vendor integrations, addressing the main connectivity criticism.

Proofpoint Core Email Protection is the enterprise tier of Proofpoint’s email security stack, built for organizations with 500+ users that need layered defense against phishing, BEC, ransomware, and data loss. We think the Nexus threat intelligence is the differentiator. The detection engine processes over three trillion emails annually, giving it a signal advantage over vendors that don’t operate at comparable scale.

Proofpoint Core Email Protection Key Features

Nexus threat intelligence feeds the detection engine with data from over three trillion emails annually, which is particularly strong on emerging campaigns and BEC patterns. You can run Proofpoint as an MX-based gateway, a cloud service, or an API integration alongside existing mail routing, which suits organizations with hybrid environments or complex mail flows. DLP, encryption, and DMARC enforcement are included without separate vendor purchases.

What Customers Say

Customers say detection quality holds up over the long haul, with consistent blocking of phishing, malware, and impersonation traffic. Built-in phishing simulation saves them buying a separate awareness training platform.

Our Take

We think Proofpoint Core fits large enterprises that need depth, scale, and policy control beyond what Microsoft Defender or midmarket tools provide. If you run hybrid mail or need DLP and encryption in the same platform, this is one of the few vendors that handles the full stack without requiring separate purchases.

Proofpoint 365 Total Protection, formerly Proofpoint Essentials, is the SMB and midmarket tier of Proofpoint’s email security stack, packaging URL defense, BEC protection, archiving, encryption, and DLP into one platform built for Microsoft 365. Proofpoint is a global leader in email security, and this product brings the company’s enterprise-grade detection engine to smaller organizations at a price point that starts from around $3 per user per month.

Proofpoint 365 Total Protection Key Features

Proofpoint’s multi-layered detection engine covers spam, malware, phishing, and BEC. URL Defense blocks malicious email links at time of click, and Supernova BEC detection and predictive URL scanning catch threats that native Microsoft 365 filters miss. The inline filtering deployment option gets you up and running in under five minutes without MX record changes, which makes the platform viable for teams without dedicated mail engineering bandwidth. Archiving, encryption, and DLP are bundled without separate vendor contracts, and multi-domain support works well for SMB and MSP environments.

What Customers Say

Customers say the admin interface is straightforward, with quick user management, log searches, and quarantine release. The daily spam digest, multi-domain support, and built-in encryption come up as practical features that save time for lean IT teams.

Our Take

We think Proofpoint 365 Total Protection fits SMBs and lower midmarket teams running M365 that want Proofpoint’s detection engine without enterprise pricing. The bundled compliance tooling is a real differentiator at this price point. SE Labs testing has rated Proofpoint among the highest for email threat detection accuracy across market-leading vendors.

Sublime Security is a programmable email security platform built for Microsoft 365 that gives security teams full visibility into why messages get flagged. We think the transparency is the real differentiator. Most email security tools are black boxes. Sublime shows its working, which matters for teams that need to tune detections, investigate incidents, or satisfy compliance requirements.

Sublime Security Key Features

Sublime’s MQL query language lets you write custom detections, build automated triage workflows, and integrate alerts into Slack or email. The EML Analyzer provides a VS Code-like interface where detection engineers can inspect messages, test rules, and build new logic. Out-of-the-box accuracy is high enough to skip long tuning cycles during deployment, and the engineers who built the product double as the support team.

What Customers Say

Customers say accuracy out of the box is high enough to skip long tuning cycles, and the engineers being the support team comes up repeatedly as a differentiator. According to customer feedback, regional hosting inconsistencies mean new features take time to reach non-US customers.

Our Take

We think Sublime fits midmarket and enterprise teams with the technical capability to write rules and a preference for visibility over plug-and-play simplicity. If your security team wants programmable detection and direct access to the people who built the platform, Sublime is worth evaluating.