Most security leaders do not need another reminder that email is the path of least resistance. What has changed is the mix of techniques that make social engineering work at scale. Phishing kits that once looked generic now use generative models to create convincing, context‑aware lures. Adversaries also spend more time stealing identities than building malware. IBM’s 2025 X‑Force Threat Intelligence Index describes an 84 percent year‑over‑year rise in infostealers delivered via phishing emails, along with a persistent pattern where nearly one-third of intrusions use valid credentials rather than traditional exploits. Those two ideas, taken together, explain why organizations are investing in email controls that understand people, not just payloads
The second shift is speed. People make decisions in seconds once a message feels urgent or familiar. That reality changes the role of an email gateway or an API‑integrated tool. Pre‑delivery filtering is necessary. Post‑delivery removal is now equally critical. If a vendor cannot find and retract a bad message from inboxes quickly, you will end up measuring all the wrong things after the fact.
It helps to get our definitions straight before comparing platforms. Two operating models dominate modern deployments.
Security programs benefit when decisions follow the data, not the sales deck. IBM’s 2025 X‑Force report is clear on two fronts. First, the 84 percent increase in phishing‑delivered infostealers highlights the growing focus on stealing credentials at scale. Second, valid credentials were involved in nearly one-third of intrusions, which means incidents often begin with users who appear legitimate after a successful phish or an infostealer infection.
This aligns with what many tenant administrators already see. Attacks that “log in rather than break in” blend into normal activity. They create forward rules, plant OAuth apps, or hijack reply chains to spread laterally. The security control that wins is the one that can learn normal patterns and flag small anomalies fast, while still giving administrators tools to correct misconfigurations that increase exposure. It is also why Microsoft emphasizes foundation controls such as Safe Links for time‑of‑click URL scanning, Safe Attachments for detonation of suspicious files, and anti‑phishing policies that protect VIPs and common senders by default.
A final point from human factors research is worth carrying forward. The SANS 2025 Security Awareness Report reiterates that social engineering remains the number one threat and that changing culture takes patient work. That does not replace technical controls. It simply reminds us that training and workflow design reduce the number of opportunities attackers can exploit.
Most RFPs devolve into a feature checklist. A better way is to look at outcomes and ask how each platform supports the workflows that produce those outcomes. Use the following lens.
Step #1: Begin with identity‑aware detection. If identity is the new perimeter, your platform must look beyond binary signatures. You want systems that understand conversational context, sender behavior, and relationship history. That is the only sustainable way to detect business email compromise, vendor spoofing, and lateral phish that do not carry obvious malware. IBM’s observation about intrusion methods is a useful benchmark when you ask vendors to prove how they detect identity‑centric attacks at scale.
Step #2: Next, confirm time‑of‑click link analysis and detonation for attachments. Threat actors routinely weaponize links after delivery and hide payloads in uncommon file types. Microsoft’s documentation on Safe Links and Safe Attachments explains how time‑of‑click and sandboxing reduce this window. Platforms that interoperate cleanly with those controls often drive the best cost‑benefit in Microsoft 365 environments.
Step #3: Then test post‑delivery remediation in realistic conditions. Ask for a live demo using your tenant, with your test messages, and measure how quickly the system can find and retract a message from dozens or hundreds of inboxes. If your users click within seconds, speed here is not a luxury. It is a success criterion informed by how people behave in the real world.
Step #4: Finally, map outbound DLP and encryption requirements. Regulated industries need policy‑based encryption and auditable actions. Seek tools that automate the “how” of secure delivery rather than asking users to decide. Microsoft covers much of the inbound surface area. You will often need a complementary control to ensure sensitive data leaves the organization in a managed way.
Microsoft’s native email and collaboration security runs inside Microsoft 365, so there’s no gateway change or extra plumbing. It extends protection across Exchange Online, SharePoint, OneDrive, and Teams with unified policies and dashboards. A strong anchor layer whether you run it solo or alongside a second vendor.
Natively built into Microsoft 365 with centralized administration in the Defender portal. Works out of the box for mail and collaboration workloads, and plays well in layered architectures.
Multi‑phase filtering with Safe Links and Safe Attachments to stop phishing, malware, and zero‑day content, plus identity‑aware signals shared across the Microsoft security stack.
Zero‑hour auto purge to remove threats after delivery, automated investigation/remediation to shorten dwell time, and hunting/Explorer for fast triage.
Best for Microsoft‑centric organizations that want native telemetry, RBAC, and audit readiness across the M365 estate.
Best Cloud Email Security Platforms for Enterprises 2025 2026: Mimecast Email Security (Cloud Gateway)
Mimecast adds a cloud secure email gateway in front of Google Workspace or Microsoft 365 and can bundle archiving, continuity, and DMARC in one platform. It’s designed to harden your perimeter while giving users clear banners and admins deep policy control. A good choice when compliance and discovery sit next to threat defense.
Cloud SEG that attaches to Gmail or Exchange Online with straightforward policy controls and optional add‑ons (archiving, continuity, DMARC/governance).
AI‑driven detection, brand/impersonation defenses, and policy depth designed to catch targeted phishing and ransomware.
Time‑of‑click evaluation, retrospective remediation, and integrations to streamline incident investigations and response.
Strong in regulated and discovery‑heavy environments needing security plus continuity/e‑discovery under one operational umbrella.
3. Check Point Harmony Email & Collaboration (Avanan)
Harmony connects via API to Google Workspace and Microsoft 365—more in line with modern enterprise email security solutions than legacy gateway-heavy options such as Forcepoint Email Security—so rollout is fast and agentless. It extends beyond email to shared content across email and collaboration tools, helping protect business communication with DLP, malware sandboxing, and file sanitization. Built to catch email threats that native layers miss, then clean them up automatically.
API‑based, inline or detect‑and‑remediate modes, with coverage for mail and collaboration apps without rerouting mail and with seamless integration into an existing security stack.
Advanced sandboxing, phishing/BEC protection, file sanitization, and DLP strengthen threat detection capabilities, reduce risk from links, attachments, and insider or accidental exposure, and help prevent data leaks; content analysis, reputation checks, and sandboxing also block malicious emails before they reach user inboxes.
Continuous mailbox monitoring can scan internal email traffic, while granular policy controls support staged enforcement alongside governance needs such as DMARC, archiving, and continuity across your existing email infrastructure.
Great fit for cloud‑first teams that want advanced email security, comprehensive threat intelligence, and a flexible email security provider approach across collaboration tools with policy depth.
4. OpenText Email Security (Core Email Threat Protection + Core Email Encryption)
OpenText combines multi‑layer threat filtering with policy‑based encryption/DLP from one console. Time‑of‑click URL checks, attachment sandboxing, and machine learning cover inbound, outbound, and internal mail as advanced email security that fits into existing email infrastructure rather than replacing it. Built for organizations that want one vendor for both stopping attacks and helping protect sensitive data with enforceable controls as part of a broader security strategy.
Cloud‑delivered threat protection and encryption/DLP that layer into Google Workspace or Microsoft 365 without complex mail‑flow changes; managed in a unified console. This email security solution hooks directly into modern cloud platforms through API-based deployment, requires zero network rerouting, and supports post-delivery removal from user inboxes.
ML‑driven filtering, URL rewriting/time‑of‑click inspection, and cloud sandboxing help block malicious emails and broader email threats, including phishing attacks, ransomware, impersonation, BEC, and spam across all mail directions. Mailbox monitoring can also scan internal email traffic and protect business communication across collaboration apps. Message retraction/quarantine with full audit trails; encryption applies automatically via data loss prevention policies, which can scan outgoing emails and attachments for sensitive information and then block, quarantine, or encrypt as needed, using best‑method delivery (TLS, S/MIME, secure portal) to reduce user friction.
Well‑suited to compliance‑driven, data‑sensitive organizations that value integrated threat defense and encryption/DLP with straightforward governance reporting, including support for GDPR and HIPAA requirements. For teams comparing email security companies, the fit is strongest when aligned to an organization’s specific risk profile. Harmony also integrates cleanly with the existing security stack, positioning it as an email security provider with strong threat detection capabilities and comprehensive threat intelligence.
5. Barracuda Email Protection / Email Gateway Defense
Barracuda typically runs as a secure email gateway in front of Gmail or Microsoft 365, with clear, documented deployment patterns. It brings layered filtering, time‑of‑click URL protection, sandboxing, encryption, and data loss prevention, plus continuity options. A pragmatic piece of email security software for teams who prefer SEG‑style control, including those comparing it with cisco secure email.
Cloud SEG with guided inbound/outbound configuration for Google Workspace and Microsoft 365; continuity features to keep mail flowing.
Layered spam/phishing/malware filtering, link protection at time‑of‑click, reputation checks, and sandboxing for malicious attachments; outbound filtering and encryption align to DLP policies.
Incident response tools and policy automation for quick removal and containment; approachable admin for day‑to‑day tuning, where detection accuracy and false-positive handling matter. AI improves detection by analyzing large volumes of email traffic for subtle malicious intent that older systems often miss. Ask vendors about detection rates, how they use global threat intelligence, and how they handle false positives, since too many bad flags can create operational inefficiencies and extra work for your security team. That is especially important for defending against cyber threats and more targeted attacks.
Appealing to SMB and mid‑market teams that want predictable operations and a familiar gateway model for managing email security tools. When comparing email security companies, including the best email security companies, evaluate products like this against your organization’s specific risk profile and broader security strategy.
6. Abnormal Security (Cloud Email Security Platform)
Abnormal is an API‑based, cloud‑native platform that integrates with Google Workspace and Microsoft 365 without altering mail flow, positioning it alongside Barracuda and Cisco Secure Email when buyers compare best email security companies for defending against sophisticated cyber threats. It models “known‑good” behavior to spot social engineering attacks like business email compromise BEC, supplier fraud, and account takeovers. Designed to save analyst time with automated triage and remediation.
Mailbox‑level API integration with rapid deployment and deep visibility, unlike Secure Email Gateways that require MX‑record changes to route mail through the vendor first, excel at perimeter spam filtering and custom controls, but can add delivery friction and miss some internal‑to‑internal threats. Many organizations are moving away from traditional SEGs in favor of API‑based alternatives for simpler deployment.
Behavioral AI focuses on identity, relationships, and communication patterns, using threat intelligence to flag anomalies that can reveal payload‑less phishing, zero day threats, malicious links, and other sophisticated threats, including targeted attacks that bypass microsoft defender for office 365 or broader microsoft security layers.
Automates triage of user‑reported emails, clusters campaign‑related messages, and removes malicious mail with automated incident response to reduce manual workload for analysts and help contain compromised accounts.
Best for teams wanting automation and mailbox‑level insight layered on native defenses without adding gateway complexity, especially where advanced threat detection and targeted attack protection are priorities beyond microsoft defender or microsoft defender for office.
7. IRONSCALES (Adaptive AI Email Security)
IRONSCALES delivers inbox‑level protection via API for Google Workspace and Microsoft 365 with a quick, no‑MX‑change rollout, providing advanced threat protection against evolving email based threats. Advanced enterprises often layer API-based protection over native Microsoft security controls such as Microsoft Defender for Office 365 to catch sophisticated cyber threats and social engineering attacks. Its Adaptive AI learns communication norms, while the human loop enriches detection. An agentic remediation engine cleans up at speed.
Deployment & Integration3‑click, API‑based deployment; inbox‑level visibility for internal and external traffic; integrates with SIEM/SOAR/XDR ecosystems.
Adaptive AI + NLP/NLU analyzes large volumes of email traffic, using organizational context, communication history, and anomalous behavior to catch business email compromise, compromised accounts, targeted attacks, phishing, BEC, ATO, and low-signal tactics, with real time threat detection for emerging threats. Modern platforms now prioritize intent analysis over just malicious links or files, which helps stop sophisticated threats and zero-day attacks.
Automated clustering and remediation; dynamic banners and a report-phish loop strengthen the human layer and cut response time, while targeted attack protection and threat intelligence help explain why API-based layering works as attackers increasingly use AI-generated phishing content that can bypass traditional security measures. Integrated security awareness training also supports phishing simulations and user education, and the platform can fit enterprises as well as managed service providers.
A strong option for lean security teams seeking hands-off remediation and integrated awareness and DMARC/SPF/DKIM management against advanced phishing attacks, with an approach that goes beyond native Microsoft Defender for Office 365 and is more focused than Proofpoint email protection.