Best Email Security Tools: Free and Paid

Email remains the primary attack vector for scams and cyberattacks — over 90% of successful breaches begin with a phishing email according to Verizon's DBIR. While built-in spam filters catch the obvious junk, sophisticated phishing emails consistently bypass default protections. Dedicated email security tools add the layers needed to catch what gets through.

Built-in Protections: The Baseline

Gmail

Gmail's built-in protection is strong: machine learning-based spam filtering blocks 99.9% of spam and phishing, per Google's claims. Gmail checks SPF, DKIM, and DMARC automatically and displays warnings for failed authentication. It flags external emails in Google Workspace.

Limitation: sophisticated spear-phishing that passes authentication checks (sent from compromised or look-alike domains) can bypass Gmail filters.

Outlook / Microsoft 365

Exchange Online Protection (EOP) comes free with Microsoft 365. It includes spam filtering, malware scanning, and basic phishing detection. Microsoft Defender for Office 365 (paid add-on) adds advanced threat protection including safe links, safe attachments, and attack simulation.

Apple Mail

Apple Mail's built-in protection is more limited. It relies on your email provider's server-side filtering. iCloud Mail includes basic spam filtering but lacks the advanced phishing detection of Gmail or Outlook.

Recommended Email Security Tools

IsThisAScam — Best for On-Demand Email Analysis

IsThisAScam is not a traditional email security gateway — it is an on-demand analysis tool. Paste any suspicious email into the analyzer and it checks the content, links, sender patterns, domain data, and AI-generated content markers through 6 layers of detection. It is the best option for quickly verifying a specific email you are unsure about.

• Best for: Verifying specific suspicious emails on demand
• Price: Free
• Advantage: Analyzes email content, not just URLs, including AI-generated phishing detection

Proofpoint Essentials

Proofpoint is the enterprise email security leader, and Essentials brings their technology to small businesses. It provides advanced threat protection, URL defense (rewriting and scanning links in emails), attachment sandboxing, and impersonation protection.

• Best for: Small businesses needing always-on email gateway protection
• Price: From $2.50/user/month
• Advantage: Industry-leading threat intelligence, real-time URL rewriting

Abnormal Security

Abnormal uses behavioral AI to detect business email compromise and social engineering that traditional filters miss. It learns normal communication patterns and flags deviations — like a "CEO" sending a wire transfer request from an unusual device at an unusual time.

• Best for: Organizations concerned about BEC and executive impersonation
• Price: Enterprise pricing (contact for quote)
• Advantage: Behavioral analysis catches attacks that content-based filters miss

Mimecast

Mimecast provides email security, archiving, and continuity in one platform. Their Targeted Threat Protection includes URL protection, attachment sandboxing, and impersonation protection.

• Best for: Mid-size businesses wanting comprehensive email management
• Price: From $4/user/month
• Advantage: All-in-one platform including archiving and continuity

Barracuda Email Protection

Barracuda combines gateway-level filtering with AI-based impersonation detection and automated incident response. It integrates with Microsoft 365 and Google Workspace.

• Best for: Small to mid-size businesses on Microsoft 365 or Google Workspace
• Price: From $3/user/month
• Advantage: Strong integration with major email platforms, automated remediation

Avanan (Check Point Harmony Email)

Avanan deploys inline with Microsoft 365 and Google Workspace via API, scanning emails after they pass the built-in filters but before they reach the inbox. This "second layer" approach catches what Gmail and Outlook miss.

• Best for: Organizations wanting to supplement (not replace) their existing email platform's security
• Price: From $4/user/month
• Advantage: API-based deployment catches what default filters miss without disrupting email flow

Free Tools for Individuals

• IsThisAScam: Paste any email for comprehensive analysis — isthisascam.to
• Google's Enhanced Safe Browsing: Enable in Chrome settings for real-time link checking
• Thunderbird with built-in phishing detection: Free email client with scam detection features
• PhishTool (free tier): Email header analysis and phishing indicator identification

Best Practices Regardless of Tool

1. Enable 2FA on all email accounts — even if credentials are stolen, 2FA blocks unauthorized access
2. Use unique passwords for each email account (password manager recommended)
3. Check email headers when uncertain about a sender
4. Never click links in unexpected emails — navigate to the site directly
5. Report phishing to your email provider (it improves their filters for everyone)

See also: best phishing protection for individuals and how to check if an email is legitimate.