7 Best Email Security Software for Microsoft 365 and Google Workspace to Stop Phishing and Reduce Breach Risk

If you run Microsoft 365 or Google Workspace, you already know email is still the easiest way for attackers to slip in. Phishing, business email compromise, and malware can bypass basic protections fast, which is why finding the best email security software for Microsoft 365 and Google Workspace feels urgent.

The good news: you do not need to guess your way through dozens of tools. This guide cuts through the noise and shows you which platforms are actually worth considering if you want stronger protection, fewer risky clicks, and lower breach exposure.

You will get a clear look at seven top options, what each one does best, and where they fit based on your environment. By the end, you will know which features matter most, how these tools help stop phishing, and which solution is the smartest match for your team.

What Is Best Email Security Software for Microsoft 365 and Google Workspace?

The best email security software for Microsoft 365 and Google Workspace is usually the platform that adds **advanced phishing detection, account takeover protection, and post-delivery remediation** without creating major admin overhead. For most operators, the shortlist includes **Proofpoint, Mimecast, Abnormal Security, IRONSCALES, and Avanan/Check Point Harmony Email & Collaboration**. The right choice depends less on brand recognition and more on **deployment model, API depth, and incident response workflow fit**.

Microsoft 365 and Google Workspace already include native controls, but many teams buy a second layer because **business email compromise, QR phishing, and vendor impersonation** still bypass default settings. Operators should evaluate whether they need a **secure email gateway (SEG)**, an **API-based detection layer**, or both. That decision affects cost, rollout speed, and how quickly security teams can quarantine malicious mail after delivery.

Proofpoint and Mimecast are common picks for larger or more regulated environments that want mature policy controls, encryption options, and strong continuity features. They are often better when teams need **DLP alignment, legal hold workflows, journaling support, or granular mail routing policies**. The tradeoff is that SEG-style deployments can require **MX record changes, mail flow redesign, and longer tuning cycles** than lightweight API tools.

Abnormal Security, IRONSCALES, and Avanan are frequently favored by operators prioritizing rapid deployment and modern threat detection across cloud inboxes. These tools typically connect through **Microsoft Graph or Google Workspace APIs**, which reduces mail-routing disruption and speeds implementation. In practice, API-first products are often strong at **post-delivery clawback, lateral phishing detection, and behavioral analysis**, though feature depth around continuity or complex compliance use cases can vary by vendor.

Pricing usually follows a **per-user, per-year** model, and operators should compare more than headline license cost. A tool priced at **$3 to $8 per user per month** may look similar on paper, but ROI changes if one vendor cuts phishing investigation time by 50% or eliminates a separate awareness product. Hidden cost drivers include **premium support tiers, minimum seat counts, SIEM ingestion volume, and add-ons for archiving, DLP, or incident automation**.

A practical evaluation framework is:

• Microsoft 365-heavy enterprises: prioritize Graph API coverage, Defender coexistence, and automated message remediation.
• Google Workspace-centric teams: verify Gmail API permissions, alert fidelity, and support for delegated admin models.
• Regulated organizations: check encryption, retention, continuity, and audit export requirements.
• Lean IT teams: favor low-touch deployment, strong default policies, and high-confidence auto-remediation.

For example, a 2,000-user hybrid organization may choose an API-based product first to reduce rollout friction, then add SEG controls later if supplier impersonation and attachment sandboxing remain gaps. A common Microsoft 365 investigation flow might look like this:

# Example operator workflow
1. Alert generated for impossible-travel login + suspicious inbox rule
2. Platform queries Graph API for related messages
3. Admin launches tenant-wide search and purge
4. SOAR ticket opens with impacted users and remediation steps

Integration caveats matter. Some vendors have better **Sentinel, Splunk, or Cortex XSOAR** connectors, while others offer stronger native playbooks for Slack, Teams, or ServiceNow. Also verify whether remediation actions require **read-only access, full mailbox access, or write permissions**, because security and legal teams often scrutinize those scopes during procurement.

Decision aid: choose **Proofpoint or Mimecast** if you need broad enterprise controls and continuity, and choose **Abnormal, IRONSCALES, or Avanan** if you want faster cloud-native deployment with strong behavioral detection. The best fit is the one that **reduces successful phishing incidents without adding major mail-flow complexity or alert fatigue**.

Best Email Security Software for Microsoft 365 and Google Workspace in 2025: Top Platforms Compared by Threat Detection and Ease of Deployment

For most operators, the shortlist comes down to **API-first cloud email security** versus **secure email gateway add-ons** layered on top of Microsoft 365 and Google Workspace. API-based tools usually deploy faster, inspect internal mailbox history, and remediate post-delivery threats, while gateway-centric products can block earlier in the mail flow but may add routing complexity. The right choice depends on whether you prioritize **speed to value, phishing detection depth, or mail-flow control**.

**Abnormal Security, Sublime Security, Mimecast, Proofpoint, and IRONSCALES** are the names most buyers will evaluate in 2025. Abnormal and IRONSCALES are strong for **behavioral phishing detection** and fast SaaS rollout in cloud-native environments. Mimecast and Proofpoint remain common in regulated enterprises that want **mature policy controls, archiving adjacencies, and broader messaging security suites**.

For Microsoft 365, buyers should verify whether the vendor complements or overlaps **Microsoft Defender for Office 365 Plan 1 or Plan 2**. Paying for a premium third-party layer without tuning Defender often creates duplicate quarantine workflows and unclear ownership between SecOps and messaging teams. A practical ROI test is whether the new tool reduces **business email compromise losses, help desk tickets, and manual message remediation time** within the first two quarters.

For Google Workspace, the biggest differentiators are usually **API permission scope, alert fidelity, and admin usability**, not just raw detection claims. Some vendors are excellent at executive impersonation and vendor fraud, while others are better at malware detonation, URL analysis, or outbound account takeover detection. If your environment is heavily browser-based and contractor-heavy, **identity-linked phishing detection** matters more than attachment scanning alone.

Here is a practical comparison framework operators can use during vendor review:

• Detection model: Behavioral AI for BEC, static policy rules, sandboxing, and link rewriting each catch different attack classes.
• Deployment effort: API-only tools can often be piloted in hours, while gateway changes may require MX updates, connector tuning, and rollback planning.
• Analyst workflow: Look for one-click message purge, user-reported phish triage, and SIEM/SOAR integrations with Microsoft Sentinel, Splunk, or CrowdStrike.
• Pricing tradeoff: Per-user SaaS pricing is predictable, but premium add-ons for incident response, data loss protection, or archiving can materially raise total cost.
• False positives: Executive email and finance workflows should be tested with real samples, because blocking a legitimate wire request can create business friction.

A concrete pilot scenario is a **2,500-seat Microsoft 365 tenant** with Defender already enabled. The team can connect an API-based vendor to a subset of finance, HR, and executive accounts for 14 days, then compare **detected phishing, auto-remediation speed, and user-reported misses** against Defender baselines. If the vendor finds materially more vendor fraud and account takeover signals without increasing false positives, the business case becomes easier to defend.

Implementation details matter more than demos suggest. Ask whether the platform can **retroactively search and pull malicious mail from all inboxes**, whether it supports cross-tenant operations for MSP or multi-brand environments, and how long it retains message metadata for investigations. Also confirm integration caveats such as journaling dependencies, regional data residency, and whether mailbox access is read-only or includes remediation permissions.

For teams that want a quick buying heuristic, use this decision aid:

1. Choose Abnormal or IRONSCALES if your main pain is sophisticated impersonation and you want rapid deployment with minimal mail-routing change.
2. Choose Mimecast or Proofpoint if you need deeper email governance, broader enterprise controls, or already run adjacent modules from the same vendor.
3. Evaluate Sublime Security if your team values flexible detection engineering and wants more transparent control over how threats are identified.

Bottom line: the best platform is the one that improves phishing catch rate and remediation speed **without increasing operational drag**. Buyers should score vendors on **deployment friction, overlap with native Microsoft or Google protections, and measurable reduction in BEC risk**, not just headline AI claims.

How to Evaluate Email Security Software for Microsoft 365 and Google Workspace Based on Phishing Protection, BEC Defense, and AI Detection

Start by separating vendors into two deployment models: API-based mailbox protection and secure email gateway (SEG) filtering. API tools sit inside Microsoft 365 or Google Workspace after delivery, while SEGs inspect mail before it lands. In practice, operators often prefer layered coverage because SEG-only products can miss internal-to-internal phishing and API-only tools may not stop malicious messages before user exposure.

The first scoring category should be phishing efficacy, not feature count. Ask for detection results across credential-harvest links, QR-code phishing, URL redirection chains, and weaponized cloud-sharing links from OneDrive, SharePoint, or Google Drive. A serious vendor should explain how it rewrites URLs, detonates links at click time, and handles delayed payload activation.

For Microsoft 365 and Google Workspace, BEC defense deserves its own evaluation track because many attacks contain no malware or obvious bad links. Strong products analyze sender-recipient history, display-name impersonation, VIP targeting patterns, mailbox rules, and unusual payment language. If a vendor only talks about spam rates, that is usually a sign their BEC engine is immature.

Ask specifically how the platform detects AI-written phishing and low-signal social engineering. The better tools do not rely only on static language models; they combine behavioral baselines, graph analysis, identity signals, and message context. This matters because generative AI has reduced grammar mistakes, making traditional content heuristics far less useful.

A practical test is to run a controlled pilot with replayed threat samples from your own environment. Include user-reported phish, finance impersonation attempts, vendor invoice scams, and benign newsletters that often trigger false positives. Measure not just catches, but also triage workload, remediation speed, and whether the product can retroactively pull bad mail from every impacted mailbox.

Use a simple scorecard such as:

• Detection quality: phishing, BEC, lateral phishing, account takeover indicators
• Response actions: auto-remediation, mailbox search-and-destroy, user warning banners, SOAR hooks
• Platform fit: Microsoft Graph permissions, Google Workspace API scopes, multi-tenant support for MSPs
• Operational overhead: tuning effort, false positive management, analyst workflow impact
• Commercial model: per-user pricing, minimum seat count, premium modules for awareness training or DMARC

Integration depth can create hidden implementation constraints. Some vendors require broad Graph permissions such as Mail.ReadWrite and MailboxSettings.Read, which security teams or compliance reviewers may challenge. Others support Teams or Slack alerting, Sentinel ingestion, Chronicle forwarding, or ticket creation in ServiceNow, which can materially reduce response time.

Pricing tradeoffs are rarely straightforward. A tool priced at $3 to $6 per user per month may look expensive against native controls, but one prevented wire-fraud incident can justify multiple years of spend. Also check whether impersonation protection, post-delivery remediation, or DMARC enforcement are bundled, because add-on modules can raise total cost by 20% to 40%.

Vendor differences also show up in deployment speed and rollback safety. Some API products can be live in under an hour for a 1,000-seat tenant, while SEG migrations may require MX changes, mail flow connector testing, and exception handling for third-party services. If uptime risk is a concern, favor vendors that offer monitor-only mode before enforcement.

For a concrete comparison, imagine a 2,500-user company on Microsoft 365 evaluating two tools. Vendor A blocks more spam at the gateway but misses internal invoice fraud, while Vendor B catches display-name spoofing and anomalous finance requests through mailbox graph analysis. If your main loss scenario is BEC, Vendor B may deliver better ROI even with a slightly higher license cost.

Decision aid: choose the product that proves it can stop your highest-frequency phishing patterns, your most expensive BEC scenarios, and your team’s real remediation bottlenecks. In most Microsoft 365 and Google Workspace environments, that means prioritizing post-delivery search-and-remediate, identity-aware BEC detection, and low false positives over long feature checklists.

Microsoft 365 vs Google Workspace Email Security Gaps: Where Third-Party Protection Delivers the Highest ROI

Microsoft 365 and Google Workspace both include baseline email security, but neither stack fully covers modern impersonation, QR-code phishing, business email compromise, and post-delivery response workflows. For operators comparing platforms, the real question is not which suite is “secure enough,” but where native protection stops and third-party tools create measurable risk reduction. The highest ROI usually comes from closing detection gaps that generate the most help desk load, user exposure, and incident response time.

In Microsoft 365, native protection is strongest when organizations already license Defender for Office 365 Plan 1 or Plan 2, but many tenants run on Exchange Online Protection alone. That leaves meaningful gaps in advanced attachment sandboxing, automated investigation depth, user-reported phish triage, and cross-mailbox remediation speed. Operators also need to validate whether Safe Links and Safe Attachments policies are consistently applied across shared mailboxes, VIP users, and hybrid mail flow.

Google Workspace has a cleaner default security posture for many SMB deployments, but its limitations often show up in granular policy tuning, forensic visibility, and third-party response orchestration. Admins can enforce strong authentication and anti-spoofing controls, yet targeted attacks still bypass native filters through lookalike domains, compromised vendor accounts, and well-crafted text-only phishing. In practice, Google environments often add third-party tools sooner when security teams need better alert context and faster mailbox-level remediation.

The strongest ROI cases for third-party protection usually fall into four operational buckets:

• Impersonation and BEC defense: Better detection of display-name spoofing, domain lookalikes, VIP targeting, and supplier fraud.
• Post-delivery response: Faster search-and-purge actions across inboxes after a phish is reported or newly classified as malicious.
• User reporting and triage: Outlook and Gmail add-ins that reduce SOC manual review time and improve analyst consistency.
• URL and attachment analysis: Stronger sandboxing, time-of-click inspection, and payload detonation than native defaults in lower-tier licenses.

Pricing tradeoffs matter more in Microsoft 365 than many buyers expect. If upgrading from a lower plan to E5 or adding Defender for Office 365 Plan 2 costs nearly as much as a dedicated email security layer, buyers should compare operational outcomes instead of line-item cost alone. A third-party product can be the better buy when it delivers API-based retroactive remediation, security awareness tie-ins, and better detection efficacy without forcing a broader suite upgrade.

A practical decision model is to compare native controls against third-party tooling using a simple matrix:

1. Current license reality: EOP only, Defender P1/P2, or Google Workspace Business/Enterprise.
2. Attack profile: BEC-heavy, malware-heavy, or compliance-sensitive.
3. Response maturity: Can the team investigate and remediate suspicious messages in under 15 minutes?
4. Integration constraints: API deployment, MX redirect, journaling, SIEM export, and incident workflow compatibility.

For example, a 1,200-user professional services firm on Microsoft 365 Business Premium may already have decent baseline filtering, but still lose hours each week to executive impersonation and vendor fraud review. If a third-party platform costing $3 to $6 per user per month eliminates even one wire-fraud near miss or cuts analyst triage by 10 hours monthly, the payback is often immediate. By contrast, a smaller Google Workspace team with low phishing volume may get better ROI from DMARC enforcement and security awareness training before buying a premium gateway.

Implementation differences also affect ROI. API-based deployment is usually faster and less disruptive than changing MX records, but some vendors reserve deeper inline filtering features for gateway mode. Buyers should also confirm whether the product supports internal mail scanning, Teams or Google Chat signal correlation, and automated rollback of malicious messages, because those details often separate a dashboard tool from a real risk-reduction layer.

Example operator check: Required controls = [VIP impersonation, user-report button, retroactive purge, SIEM export, API deploy]. If your current suite misses three or more of those controls, third-party protection is usually justified financially and operationally. Bottom line: Microsoft 365 often needs supplementation sooner in lower-tier licensing, while Google Workspace typically benefits most when response automation and BEC defense become business-critical.

Pricing, Implementation, and Vendor Fit: How to Choose the Right Email Security Software for Your Team Size and Compliance Needs

For most operators, the buying decision comes down to **license model, deployment friction, and compliance coverage**. The best email security software for Microsoft 365 and Google Workspace is not always the platform with the most features; it is the one that fits your **mail flow, staffing level, and risk profile** without creating long rollout delays.

Pricing usually falls into three buckets: **per-user SaaS licensing**, **mailbox add-ons**, or **bundled platform suites**. Entry pricing often starts around **$2 to $6 per user per month** for baseline phishing and malware protection, while advanced plans with **API-based post-delivery remediation, sandboxing, and DLP** can push into the **$8 to $15+ range**.

Buyers should verify what is actually included in the quote. Some vendors charge separately for **archiving, security awareness training, DMARC management, incident response retainers, or message encryption**, which can make an apparently cheaper tool more expensive than a bundled competitor over a 24- or 36-month term.

Implementation method matters as much as price. Vendors typically deploy through either **MX redirection/secure email gateway routing** or **API integration with Microsoft 365 and Google Workspace**, and the operational tradeoffs are significant for both security teams and messaging admins.

• Gateway-first tools inspect mail before delivery and can block threats upstream, but they may require **DNS changes, connector setup, SPF/DKIM alignment checks, and mail-flow testing**.
• API-based tools are often faster to pilot because they connect directly to tenant mailboxes, but they may act **after delivery**, which means users can briefly see malicious messages before automated remediation removes them.
• Hybrid models combine both approaches and are often preferred by regulated teams that want **pre-delivery filtering plus post-delivery detection for account takeover and lateral phishing**.

Microsoft 365 shops should ask whether the product complements or replaces **Microsoft Defender for Office 365**. If you already pay for E5 or Defender Plan 2, the strongest ROI may come from a vendor that adds **better impersonation detection, cross-tenant threat intelligence, or faster analyst workflows** rather than duplicating core protection you already own.

Google Workspace environments need extra scrutiny around **OAuth scope permissions, shared drive visibility, and alerting integrations**. Some vendors are clearly stronger in Microsoft ecosystems and treat Google support as secondary, which can show up in weaker remediation depth, fewer admin playbooks, or limited investigation telemetry.

Compliance buyers should map product capabilities directly to control requirements. For example, a healthcare or financial team may need **message encryption, legal hold support, immutable archiving, DLP policies, and detailed audit logs** to support HIPAA, SEC, FINRA, or internal retention standards.

A practical pilot should test more than detection rates. Measure **time to deploy, false-positive volume, admin training needs, SIEM/SOAR integration quality, and rollback complexity** if the product affects production mail routing.

Here is a simple evaluation pattern security teams often use during a 14-day proof of concept:

Score = (Phish catch rate * 0.35) + (Low false positives * 0.20) +
        (Implementation effort * 0.15) + (Compliance fit * 0.15) +
        (Reporting/IR workflow * 0.10) + (Net cost * 0.05)

As a real-world example, a 500-seat company comparing a **$3.50/user gateway product** with a **$9/user API-plus-IR platform** may see a yearly spread of **$33,000**. But if the higher-tier tool removes two hours of triage per week, improves post-delivery cleanup, and reduces one credential phishing incident, the **labor and incident-cost savings** can outweigh the license delta.

Vendor fit usually tracks team maturity. **Lean IT teams** often prefer strong defaults, managed tuning, and fast deployment, while **mature SOCs** prioritize granular policy controls, hunting data, webhook support, and deeper integration with Sentinel, Splunk, or Chronicle.

Decision aid: choose the vendor that delivers the best **risk reduction per operational hour**, not just the lowest per-user quote. If you are heavily invested in Microsoft or Google native controls, prioritize a platform that **fills protection gaps, proves ROI in pilot metrics, and meets compliance needs without adding mail-flow fragility**.

FAQs About the Best Email Security Software for Microsoft 365 and Google Workspace

What should operators compare first? Start with the control plane: API-based deployment, MX redirection, or a hybrid model. **API-based tools** are usually faster to deploy in Microsoft 365 and Google Workspace, while **secure email gateway products** can offer deeper pre-delivery inspection but add routing complexity.

How much does pricing usually vary? Most buyers will see pricing split into three bands: basic phishing protection, advanced BEC and account takeover defense, and full-suite platforms with archiving or DLP. In practice, **per-user annual pricing often ranges from roughly $3 to $12+ per user per month**, and costs rise quickly if you need impersonation protection, incident response, or mailbox backup in the same contract.

Is Microsoft Defender or Google native protection enough? For some small teams, yes, especially if they already pay for premium Microsoft 365 or Google Workspace tiers. But many operators still add a third-party layer for **better executive impersonation detection, post-delivery remediation, user reporting workflows, and cross-tenant visibility**.

What implementation constraint gets missed most often? Buyers underestimate how much identity and permission scoping matters during rollout. A tool may need tenant-wide admin consent, mailbox read permissions, message trace access, and SIEM integration, which can trigger legal, privacy, or works council review in larger organizations.

How do Microsoft 365 and Google Workspace deployments differ? Microsoft 365 environments often involve Exchange Online policies, Defender overlap, and Entra ID conditional access coordination. Google Workspace deployments are usually lighter operationally, but admins should verify **API quota behavior, journaling needs, and alert export options** before standardizing on a vendor.

Which vendor differences matter in real operations? Focus less on marketing labels and more on workflow fit. Key gaps show up in areas like:

• Time-to-remediate: Can the platform retract malicious emails from all inboxes in minutes?
• Detection depth: Does it catch vendor fraud, thread hijacking, and lookalike domains?
• Analyst experience: Are investigation timelines, message headers, and user-reported samples easy to review?
• Automation: Can it push incidents into Sentinel, Splunk, or SOAR tools without custom scripting?

What does a practical evaluation look like? Run a 14- to 30-day pilot using real mail flow, not vendor demos alone. Measure **phish catch rate, false positives, remediation speed, and help desk ticket volume**, then compare those metrics against licensing cost and deployment effort.

Here is a simple operator checklist for a proof of concept:

POC success criteria
- Detect impersonation of CEO/CFO display names
- Auto-remediate confirmed phishing emails in under 5 minutes
- Sync alerts to SIEM with user, sender, and message ID fields
- Keep false positives under 0.1% of inbound mail
- Support both Microsoft 365 and Google Workspace if hybrid

Where does ROI usually come from? The biggest return is not just blocked malware. It comes from **fewer account compromise events, less analyst triage time, lower wire fraud exposure, and faster end-user reporting**, especially in organizations with finance, legal, or executive assistants frequently targeted by BEC.

What is the fastest decision aid? If you need tight native alignment and already license premium controls, validate Microsoft or Google first. If you need **stronger BEC detection, cleaner remediation workflows, or multi-platform consistency**, a third-party email security layer often justifies the spend.