7 Best Email Security Software for Microsoft 365 and Google Workspace to Stop Phishing and Cut Risk Faster

If you run Microsoft 365 or Google Workspace, you already know how fast phishing, spoofing, and account takeovers can slip past basic filters. Finding the right email security software for microsoft 365 and google workspace can feel overwhelming when every vendor claims better detection, easier setup, and fewer false positives.

The good news: this guide cuts through the noise and helps you compare the best options faster. We’ll show you which tools are best for blocking phishing, improving visibility, protecting users after delivery, and reducing risk without creating extra admin pain.

You’ll get a clear breakdown of 7 top platforms, what each one does well, where it fits best, and what to watch out for before you buy. By the end, you’ll have a shorter shortlist and a much easier path to choosing the right protection for your environment.

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

Email security software for Microsoft 365 and Google Workspace is a layer of protection that sits in front of, inside, or alongside your cloud email stack to stop phishing, business email compromise, malware, account takeover, and data leakage. Native protections from Microsoft and Google cover baseline spam and reputation filtering, but many operators buy third-party tools to close gaps in impersonation detection, post-delivery remediation, and user reporting workflows. In practice, these products reduce the number of malicious emails that reach inboxes and shorten response time when one slips through.

Deployment usually follows one of two models: API-based integration or secure email gateway/MX rerouting. API tools connect through Microsoft Graph or Google Workspace APIs and scan mailboxes, message metadata, links, and user behavior after delivery or near-real time. Gateway tools inspect mail before it lands, which can improve blocking efficacy, but they may add mail-flow complexity, journaling requirements, and routing dependencies.

Operators should evaluate what the product actually does beyond the marketing label. The strongest platforms combine several control layers:

• Inbound threat detection for phishing, spoofing, QR code attacks, and malicious attachments.
• Account compromise monitoring using impossible travel, suspicious inbox rule creation, or anomalous OAuth consent events.
• Post-delivery response to pull a bad message from every mailbox after detection.
• Data loss and outbound inspection for sensitive information, vendor fraud, or accidental mis-sends.
• User coaching and reporting so employees can report suspicious mail from Outlook or Gmail add-ins.

A concrete Microsoft 365 example is a phishing email that passes SPF and DKIM because it comes from a compromised vendor mailbox. Native filtering may allow delivery if the sender domain has a good reputation, but a higher-end tool can flag display-name impersonation, abnormal sender-recipient relationship patterns, and suspicious payment language. That matters in real operations, because business email compromise losses often come from socially engineered invoices rather than malware.

Implementation details have budget and staffing implications. API-based products are usually faster to roll out, often in a few hours, because they require admin consent rather than MX changes, but they may depend on throttled API access and need broad mailbox permissions that security teams must review. Gateway products can offer stronger pre-delivery control, yet they often require DNS cutovers, transport rule changes, and tighter coordination with the messaging team.

Pricing also varies more than buyers expect. Many vendors charge roughly $3 to $12 per user per month depending on whether the package includes awareness training, DMARC services, archiving, or incident response automation. A 1,000-user environment can therefore range from about $36,000 to $144,000 annually, so ROI often hinges on whether the platform replaces multiple tools or prevents even one wire-fraud event.

For Google Workspace, buyers should check integration depth carefully. Some vendors support Gmail mailbox scanning well but offer weaker controls for Google Drive link analysis, OAuth app visibility, or admin alerting compared with their Microsoft 365 coverage. If you operate a mixed M365 and Google environment, confirm that quarantine actions, search-and-destroy, and user report buttons work consistently across both ecosystems.

A simple operator check is to ask vendors for proof of workflow coverage, not just detection claims. For example, your team may need a query or automation like if threat_type == "BEC" then retract_message(all_mailboxes) to remove a malicious invoice from every inbox within minutes. Best-fit buyers prioritize fast remediation, strong impersonation controls, and low-friction deployment over headline detection percentages alone.

Takeaway: email security software for Microsoft 365 and Google Workspace is not just spam filtering; it is an operational control plane for threat prevention, investigation, and mailbox-level response. Choose based on deployment model, cross-platform support, and measurable reduction in phishing exposure, not brand familiarity alone.

Best Email Security Software for Microsoft 365 and Google Workspace in 2025

For most operators, the shortlist starts with Abnormal Security, Proofpoint, Mimecast, Microsoft Defender for Office 365, and IRONSCALES. These vendors all support Microsoft 365, while Google Workspace coverage is strongest with Abnormal, Mimecast, IRONSCALES, and selected Proofpoint deployments. The real buying difference is not basic spam filtering, but post-delivery detection, account takeover response, and API-based remediation speed.

Microsoft Defender for Office 365 is usually the cost-control option for organizations already paying for E5 or Business Premium. It delivers strong native protection, Safe Links, Safe Attachments, and tight integration with Entra ID, Purview, and Defender XDR. The tradeoff is that operators often need more tuning, more investigation expertise, and stronger internal processes to match the managed efficacy claims of premium third-party vendors.

Abnormal Security is a strong fit for teams prioritizing business email compromise, vendor fraud, and lateral phishing detection. Its API-first deployment is attractive because there is no MX reroute requirement, which reduces rollout friction for cloud-first estates. Buyers should still validate mailbox API permissions, data residency requirements, and whether premium functionality like takedown or automated response is bundled or sold separately.

Mimecast remains relevant for operators that want a broader platform spanning email security, continuity, archiving, and awareness. That breadth can improve ROI if you are consolidating suppliers, but it can also mean more implementation planning and more policy administration. In mixed Microsoft 365 and Google Workspace environments, Mimecast is often attractive when the security team wants one policy layer across both ecosystems.

Proofpoint is still a serious enterprise contender, especially where regulated workflows, targeted attack protection, and mature incident response processes matter. It is often strongest in larger environments that can support gateway-centric architecture and formal mail flow design. For smaller teams, the downside may be higher operational overhead and less deployment simplicity compared with lightweight API-native tools.

IRONSCALES stands out for phishing response workflows, end-user reporting, and automated remediation. It is commonly evaluated by lean IT and security teams that need faster user-driven detection without building a large SOC function. The key question is whether its detection depth and broader platform scope align with your risk profile better than a more comprehensive suite.

Pricing varies widely, and buyers should model total annual cost per protected mailbox rather than headline list price. Native Microsoft protection may look cheapest if already licensed, while specialist tools can justify the premium by reducing fraudulent payment incidents, analyst review time, and account takeover dwell time. A practical benchmark is to compare the platform cost against one prevented BEC loss, which can easily exceed $50,000 in a mid-market finance workflow.

Implementation details matter more than feature grids. Ask whether the product supports API deployment, secure email gateway mode, or both, and confirm how it handles internal-to-internal phishing, shared mailboxes, delegated access, and automated quarantine rollback. Also verify integration with Teams, Slack, SIEM, SOAR, and identity controls if your response playbooks extend beyond email.

A simple evaluation checklist helps separate marketing from operational fit:

• Deployment model: API-only, gateway, or hybrid.
• Cloud coverage: full support for Microsoft 365, Google Workspace, or both.
• Detection focus: BEC, impersonation, malware, QR phishing, and account takeover.
• Response actions: auto-remediation, user coaching, takedown, and workflow automation.
• Commercial fit: mailbox minimums, bundle discounts, and incident-response add-ons.

For example, a security team might validate message remediation through Graph API after a phishing simulation:

Connect-MgGraph -Scopes "Mail.ReadWrite"
Get-MgUserMessage -UserId analyst@company.com -Top 5
# Confirm suspicious message can be located and removed at scale

Decision aid: choose Defender for lowest incremental cost, Abnormal for high-confidence BEC defense, Mimecast for platform consolidation, Proofpoint for enterprise-grade governance, and IRONSCALES for lean-team phishing response. The best product is the one that fits your mail architecture, staffing model, and fraud exposure, not the one with the longest feature sheet.

How to Evaluate Email Security Software for Microsoft 365 and Google Workspace for Phishing, BEC, and Account Takeover Protection

Start with the deployment model, because **API-based tools and secure email gateways solve different problems**. API-based products connect directly to Microsoft 365 or Google Workspace and inspect delivered mail, user behavior, and mailbox history. Gateways sit inline before delivery and are stronger for **pre-delivery blocking, mail flow control, and external routing enforcement**.

For most operators, the best shortlist includes vendors that support **both API and inline modes**. That matters if you need to catch sophisticated BEC that bypasses traditional filtering, while still enforcing transport rules, attachment detonation, and URL rewriting. Ask each vendor which protections require mailbox API access versus MX record changes, because implementation friction affects rollout speed and rollback risk.

Focus next on phishing and BEC detection depth, not just generic spam accuracy. **Display-name impersonation, lookalike domains, QR-code phishing, vendor payment fraud, and internal-to-internal abuse** are the attacks that create real financial loss. A vendor claiming “AI phishing protection” should show exactly how it detects executive impersonation, unusual payment language, and compromised supplier threads.

Use a scorecard during demos and proof-of-concept reviews:

• Identity abuse coverage: detects spoofing, domain impersonation, and VIP targeting.
• Account takeover signals: impossible travel, suspicious OAuth grants, abnormal inbox rule creation, and mass-forwarding behavior.
• Post-delivery response: can quarantine or retract messages already in user inboxes within minutes.
• User remediation: one-click report button, automated triage, and SOAR or SIEM export.
• Cross-platform support: feature parity across Microsoft 365 and Google Workspace, not just basic compatibility.

Integration quality often separates enterprise-ready tools from lightweight add-ons. In Microsoft 365, verify support for **Graph API scopes, Defender coexistence, Exchange Online mail flow rules, and Sentinel integration**. In Google Workspace, confirm support for **Gmail API access, Security Investigation Tool workflows, and alert exports to Chronicle or third-party SIEMs**.

Implementation constraints are easy to underestimate. Some vendors need broad read access to every mailbox, which can trigger legal, privacy, or works council review in regulated environments. Others require MX cutover or journaling changes, which may complicate hybrid Exchange deployments, third-party encryption services, or existing secure email gateways.

Measure pricing against the incidents you expect to prevent, not just license cost. **API-only products commonly price per user per month**, while full suites may bundle security awareness training, DLP, archiving, or incident response. A $3 to $8 per-user delta becomes material at 5,000 seats, but one prevented wire-fraud event can offset several years of subscription spend.

Ask vendors for hard performance data from similar environments. Useful buyer questions include:

1. What is the median time to remediate a malicious delivered email?
2. How many false positives per 1,000 mailboxes per month should we expect?
3. Can detections correlate mailbox behavior with IdP events from Entra ID or Google Cloud Identity?
4. What admin actions are automated versus analyst-driven?

A practical test scenario is more revealing than a polished demo. For example, send a simulated invoice from micros0ft-support.com, then follow with a legitimate-looking reply chain requesting a bank detail change. **Strong products should flag domain similarity, conversation hijacking, and anomalous payment language**, then let analysts pull all related messages tenant-wide.

Finally, evaluate operational fit after day-1 deployment. The best platform is not the one with the longest feature list, but the one your team can tune, investigate, and trust under pressure. **Choose the vendor that delivers fast remediation, low false positives, and clean integration with your existing Microsoft 365 or Google Workspace security stack**.

Pricing, ROI, and Total Cost of Ownership for Email Security Software Across Microsoft 365 and Google Workspace

Pricing for email security software usually lands on a per-user, per-month model, but operators should evaluate far beyond headline seat cost. In Microsoft 365 and Google Workspace environments, the real buying question is whether the tool reduces phishing exposure, admin labor, and incident recovery time enough to justify another control layer.

Most vendors segment pricing into three bands. Gateway filtering tiers often start around $2 to $4 per user per month, API-based detection and post-delivery remediation commonly sits near $3 to $7, and premium bundles with awareness training, DLP, or account takeover protection can push above $8 to $12 per user monthly.

Microsoft-first buyers should compare third-party spend against what is already included in Defender for Office 365 Plan 1 or Plan 2. Google Workspace buyers need a similar exercise, especially when evaluating whether native anti-phishing, security sandboxing, and admin controls already cover baseline needs before layering on a specialist vendor.

Total cost of ownership is usually driven by four factors, not one. Operators should model:

• License overlap with Microsoft Defender, E5, or Google Workspace Enterprise features.
• Deployment model, since secure email gateways may require MX changes while API tools typically do not.
• Ongoing tuning time for impersonation policies, allow lists, user reporting, and false-positive reviews.
• Incident response savings from automated message retraction, user impact analysis, and remediation workflows.

A simple ROI model helps procurement teams avoid buying on fear alone. For example, a 2,000-user organization paying $4.50 per user per month spends about $108,000 annually. If the platform prevents one business email compromise incident worth $75,000 in direct loss and saves 15 admin hours per month at $60 per hour, the annual avoided cost reaches roughly $85,800 before factoring in legal, downtime, or reputational impact.

Use a spreadsheet or script to compare scenarios consistently. A lightweight example:

users = 2000
ppm = 4.50
annual_license = users * ppm * 12
admin_savings = 15 * 60 * 12
incident_avoidance = 75000
roi_delta = (admin_savings + incident_avoidance) - annual_license
print(annual_license, roi_delta)

Implementation constraints vary meaningfully by vendor architecture. Gateway products can provide stronger pre-delivery controls and link rewriting, but they may introduce cutover risk, mail flow troubleshooting, and more coordination with DNS, journaling, and transport rules. API-based tools are faster to activate, but some have narrower coverage for outbound policy enforcement or encrypted mail routing.

Integration caveats matter in mixed estates. If part of the company runs Microsoft 365 and another business unit uses Google Workspace, confirm whether the vendor offers unified policy management, consolidated reporting, and cross-tenant remediation rather than separate consoles with inconsistent detections.

Also check pricing around add-ons that quietly inflate year-two cost. Common examples include mailbox minimums, premium support, retroactive search limits, sandbox detonation quotas, and separate charges for security awareness training. These line items can materially change the economics in small and midmarket deployments.

Decision aid: if you already own strong native controls, prioritize vendors that close specific gaps such as post-delivery remediation, impersonation detection, or cross-platform visibility. If your team is lean and incident-driven, the best ROI usually comes from tools that combine fast deployment, low tuning overhead, and measurable reduction in phishing cleanup time.

Implementation Checklist: How to Deploy Email Security Software for Microsoft 365 and Google Workspace Without Disrupting Users

The safest rollout starts with choosing the right deployment model. For Microsoft 365 and Google Workspace, operators usually pick between API-based deployment, MX record rerouting, or a hybrid model that combines inline filtering with post-delivery remediation. API-based tools are typically faster to deploy and less disruptive, while MX-based gateways give deeper control over mail flow, encryption, and outbound policy enforcement.

Begin with a pre-deployment inventory so you do not break existing routing. Document your current MX records, SPF, DKIM, DMARC policy, secure email gateways, journaling rules, transport rules, and third-party apps that send mail on behalf of your domain. This step matters because many failed rollouts come from forgotten vendors like Salesforce, Zendesk, or marketing platforms that are not aligned with the new enforcement path.

A practical implementation checklist should follow a strict sequence. Skipping order increases user impact and can create false positives, delivery delays, or authentication failures. Use this operator-focused rollout plan:

• 1. Confirm tenant prerequisites: verify Global Admin access in Microsoft 365 or Super Admin access in Google Workspace, plus DNS control at your registrar or DNS host.
• 2. Audit identity and mail flow: export accepted domains, shared mailboxes, aliases, connectors, and routing exceptions before touching production.
• 3. Choose pilot scope: start with IT, finance, and security teams, but exclude executives if the vendor has not been tuned.
• 4. Deploy in monitor mode: use alert-only, audit, or inline-bypass mode for 7 to 14 days to establish baseline detections.
• 5. Tune impersonation and VIP protection: add executives, payroll staff, and vendor payment workflows to custom policies.
• 6. Validate remediation actions: confirm quarantine, banner injection, user warning prompts, and post-delivery clawback all work as expected.
• 7. Phase in enforcement: move from monitor to targeted enforcement by group, geography, or domain segment.
• 8. Measure outcomes weekly: track false positive rate, mean time to remediate, and user-reported phishing volume.

Microsoft 365 deployments usually require extra attention to mail connectors and transport rules. If the vendor inserts an inbound gateway, validate Exchange Online connectors, Enhanced Filtering for Connectors, and anti-spoof alignment so Microsoft does not misclassify the original sender IP. In Google Workspace, check routing settings, inbound gateway configuration, and whether Gmail banners overlap or conflict with the vendor’s warning labels.

For API-based vendors such as Abnormal, Sublime, or Material Security, deployment often looks lighter because you are not changing MX records on day one. A typical Microsoft Graph permission set may include read access to messages, configuration metadata, and remediation scopes. Example scope review item: Mail.ReadBasic, Mail.ReadWrite, Directory.Read.All should be approved only after security and legal review, especially in regulated environments.

Pricing and ROI differ materially by deployment approach. API-first tools often charge per mailbox and reduce implementation labor, but some lack the full outbound control of gateway products like Proofpoint or Mimecast. Gateway-based tools can justify higher cost for organizations needing DLP, continuity, or encryption, though DNS cutovers and policy tuning usually demand more operator time.

A concrete low-risk rollout for a 2,500-seat company would look like this. Week 1: connect the tenant, ingest 30 days of message telemetry, and enable monitor mode for 250 pilot users. Week 2: tune VIP impersonation and supplier fraud policies, then enforce only on high-confidence detections once the false positive rate stays below 0.1%.

Do not overlook user experience controls because disruption is often caused by poor messaging, not the filter itself. Standardize quarantine notifications, self-release permissions, escalation paths, and help desk macros before broad enforcement. If users cannot tell whether a warning banner is legitimate, they will ignore both real threats and valid business email.

The decision aid is simple: choose API-first if you want the fastest, lowest-friction deployment, and choose MX-inline if you need deeper policy control and can tolerate more implementation overhead. In either platform, a phased pilot, authentication audit, and weekly tuning cadence are the keys to deploying email security software without disrupting users.

FAQs About Email Security Software for Microsoft 365 and Google Workspace

Why add email security software if Microsoft 365 or Google Workspace already includes native protection? Native controls catch a large share of commodity spam and malware, but many operators buy an added layer for business email compromise, account takeover, and post-delivery remediation. The practical gap is usually not antivirus; it is protection against impersonation, malicious links that weaponize after delivery, and lateral abuse from compromised internal accounts.

What does deployment usually look like? Most vendors support API-based deployment into Microsoft 365 and Google Workspace, which is faster and lower-risk than changing MX records on day one. API mode typically needs read access to mail metadata, remediation permissions, and directory integration, while full inline deployment may also require mail-flow rule changes, journaling adjustments, or secure email gateway routing updates.

How long does implementation take? For a midmarket team, API onboarding can often be done in one to three days, including tenant authorization, policy tuning, and pilot validation. Inline gateway replacements can take one to three weeks because they often involve rollback planning, SPF/DKIM/DMARC verification, allowlist migration, and stakeholder testing for outbound mail behavior.

What are the main pricing tradeoffs? Pricing is usually per mailbox per month, often ranging from $2 to $12+ per user depending on whether the package includes phishing simulation, data loss prevention, archival, or incident response features. Operators should compare not just license cost, but also whether remediation is automated, whether VIP protection is extra, and whether minimum seat counts make the tool uneconomical for small subsidiaries or seasonal staffing models.

Which vendor differences matter most in real operations? Look closely at time-to-remediate, false-positive handling, and cross-suite parity between Microsoft 365 and Google Workspace. Some tools are stronger on link rewriting and attachment detonation, while others stand out for identity graphing, suspicious login correlation, or automated clawback of messages already delivered to inboxes.

What integration caveats should buyers check before purchase? Ask whether the product supports Defender for Office 365, Exchange Online Protection, Google Advanced Protection, SIEM export, SOAR playbooks, and ticketing systems such as ServiceNow or Jira. Also verify rate limits and API quotas, because aggressive retroactive mailbox scanning can create delays in large tenants with tens of thousands of mailboxes.

Can these tools improve ROI beyond blocking threats? Yes, especially when they reduce analyst workload through automated triage and bulk message remediation. For example, if a phishing campaign hits 3,000 users and the platform can identify, retract, and close related alerts in minutes, that can save dozens of help-desk hours and materially reduce exposure to credential theft.

What should a pilot test include? Use a 14- to 30-day pilot with live mail flow, a defined set of VIP users, and baseline metrics such as phishing catch rate, false positives, and median remediation time. A simple evaluation checklist might include: API setup effort, alert quality, search speed, message trace depth, and one-click quarantine or delete actions.

What does a real-world policy check look like? Many teams validate DMARC alignment and impersonation controls during rollout. For example:

Domain: example.com
SPF: pass
DKIM: pass
DMARC policy: quarantine
Display-name spoof protection: enabled
Auto-remediate confirmed phish: true

Bottom line: choose the platform that fits your mail architecture, not just the highest detection claim. If you run both Microsoft 365 and Google Workspace, prioritize consistent policy coverage, fast post-delivery response, and transparent pricing at scale before committing to a multiyear contract.