Software advice
Best AI Email Security Software in 2026
AI email security software scans inbound and sometimes outbound mail with machine learning and language models to catch phishing, business email compromise, account takeover and malicious attachments that rule-based filters miss. It protects Microsoft 365 and Google Workspace mailboxes, either through a gateway or an API connection. It is not security awareness training, a spam filter alone or a managed service that answers phishing reports for you.
Quick answer
Libraesva Email Security ranks first for buyers who want AI detection processed locally. IRONSCALES is the pick for lean teams and MSPs adding an API layer, and Microsoft Defender for Office 365 fits Microsoft shops with the lowest published price.
Choosing email security now means deciding where the AI looks at your mail and how much of the filter you keep. Gateway products change mail routing, while API products read mailboxes after delivery and pull threats back. The ranking judges detection approach, cost structure, data handling, exit effort and fit for team size, using each vendor's own pages. Challengers and focused vendors sit ahead of the largest brands. Prices are as of October 2026, and most vendors here sell by quote, so a missing price is marked as unpublished instead of guessed. Detection rates quoted by vendors are not independent measurements.
The 11 best AI email security software in 2026, ranked
There is no score. Vendors can pay for more visibility on this website, for example a higher place in a ranking or more room on a page. Commercial relationships can also affect which products we feature and how prominently. How we rank.
| # | Tool | Best for | Free plan | Entry price |
|---|---|---|---|---|
| 1 | Libraesva Email Security | Mid-size organizations that want a gateway with AI detection processed inside their own environment | Trial | Quoted |
| 2 | IRONSCALES | Lean IT teams and MSPs adding AI phishing detection to Microsoft 365 or Google Workspace | Trial | Quoted |
| 3 | Hornetsecurity 365 Total Protection | Microsoft 365 shops and MSPs wanting email security, backup and compliance in one four-tier package | No | Quoted |
| 4 | Egress (KnowBe4) | Organizations that worry about outbound data loss and misdirected email as much as inbound phishing | No | Quoted |
| 5 | Abnormal AI | Security teams fighting payload-free business email compromise and vendor fraud in Microsoft 365 or Google Workspace | No | Quoted |
| 6 | Barracuda Email Protection | Small and mid-size businesses and MSPs wanting email protection sold in tiers with a free trial | Trial | Quoted |
| 7 | Check Point Harmony Email & Collaboration | Companies that want prevention before the inbox plus coverage for Teams, Slack, SharePoint and file sharing | Trial | Quoted |
| 8 | Mimecast Advanced Email Security | Mixed environments with on-premises, hybrid and cloud mail that need gateway continuity and API options | No | Quoted |
| 9 | Proofpoint Core Email Protection | Large organizations with a security operations team that wants one vendor from email to data loss | No | Quoted |
| 10 | Microsoft Defender for Office 365 | Organizations already on Microsoft 365 wanting the cheapest published entry point for AI phishing protection | No | $2.00 per user per month (Plan 1) |
| 11 | Darktrace / EMAIL | Security teams that want mail defense learned from their own traffic rather than shared crowd intelligence | No | Quoted |
- 1
Libraesva Email Security
Libraesva Email Security takes first place because its AI claims come with a data boundary: Semantic AI, Adaptive Trust AI and the attachment sandbox are described as running locally, with no content sent to third-party analysis. It is a layered gateway sold on-premises or as private cloud, with a 30-day trial. Its reach is smaller than the American platforms, and the vendor publishes no prices.
Strong on
- Semantic AI, sandbox and URL analysis are described as local, without sharing link or message data externally.
- A 30-day free trial and on-premises or private cloud deployment give buyers a low-commitment test.
- The vendor states Adaptive Trust AI never trains on customer content.
Weak on
- Pricing is quote-only and depends on mailbox count and deployment, so comparing budgets takes a request.
- Gateway deployment means changing mail routing, unlike the API-only products in this ranking.
Skip it if: Buyers who want a mailbox add-on that deploys by API in minutes without touching mail flow. No rate card is shown; the pricing page is a quote form asking for mailbox count and deployment type.
- 2
IRONSCALES
IRONSCALES ranks second because it sits beside an existing gateway through an API with no MX change, and it packages detection, remediation, simulation and encryption in tiers. Three named AI agents handle red teaming, phishing investigation and simulations, and an MSP console manages many tenants. Pricing is entirely by quote, and the vendor's own comparison pages are marketing, so verify detection with a pilot.
Strong on
- Deploys by API in minutes and leaves the current gateway in place if you keep one.
- Plans run from Email Essentials to Email Protect 360 with encryption and data loss prevention.
- A multi-tenant console and per-client policies are built for managed service providers.
Weak on
- No plan shows a price, so cost comparison starts with a sales conversation.
- Account takeover protection and DMARC management are add-ons on some tiers, not in the base plan.
Skip it if: Organizations that need a self-hosted gateway or must keep all mail analysis on their own servers. Every plan on the pricing page says request a quote or get pricing; no number is published.
- 3
Hornetsecurity 365 Total Protection
Hornetsecurity 365 Total Protection is third because it bundles more than email filtering: four plans add AI-based advanced threat protection, archiving, Microsoft 365 backup, awareness training and DMARC management. The vendor states it runs 12 regional data centers independent of Microsoft. The AI parts of detection are only named, not explained, and the breadth can mean paying for modules you never switch on.
Strong on
- Plan 4 stacks backup, awareness training, permission control and DMARC on top of email filtering.
- The page states 12 regional data centers, separate from Microsoft's infrastructure, for data residency needs.
- AI Recipient Validation warns users about misdirected mail based on behavior.
Weak on
- Prices are not published, and the data center locations are not named on the plan page.
- AI-based detection appears only from Plan 2 upward; Plan 1 is a spam and malware filter.
Skip it if: Teams wanting a lightweight API-only add-on without archiving, backup or training bundled in. The pricing page lists no prices and sends visitors to a product request form.
- 4
Egress (KnowBe4)
Egress is fourth because it pairs inbound phishing defense with outbound protection and encryption, which most rivals here treat as extras. The site describes an adaptive model that scores human risk and changes policy per person, using contextual machine learning on a cloud API architecture. Since KnowBe4 acquired it, product names and pages are moving, so check which modules a quote actually covers.
Strong on
- Defend, Prevent and Protect cover inbound phishing, outbound data loss and certified encryption.
- Policy adapts to a measured human risk level instead of one setting for every user.
- KnowBe4's acquisition created a combined human-risk platform, useful for buyers already running KnowBe4 training.
Weak on
- The Egress site now says it is part of KnowBe4, so branding and pricing pages are mid-transition.
- Public detail on detection method, hosting and certifications was thin on the pages checked.
Skip it if: Buyers who want a published price list and documented hosting regions before a first call. No price is shown on the Egress or KnowBe4 pages checked; the route is a demo or quote.
- 5
Abnormal AI
Abnormal AI sits fifth: it leans on behavioral detection, building a baseline per employee and vendor and flagging deviations rather than matching known bad content. It deploys by API in about a minute per the vendor, needs no MX change, and extends into identity and AI-agent security. The cost is breadth: the platform reaches beyond email, and the vendor publishes neither prices nor training terms for customer data.
Strong on
- Per-person and per-vendor behavioral baselines target BEC and vendor fraud that carry no malicious payload.
- API deployment states no MX record change and automatic removal of malicious messages.
- The trust center lists SOC 2 Type II, ISO 27001, ISO 27701 and ISO 42001.
Weak on
- Pricing is unpublished, so the claimed savings against a gateway cannot be checked.
- Hosting regions, retention and model-training terms were not in the trust center text we read.
Skip it if: Organizations that want to keep a perimeter gateway as the main control and only need basic filtering. The pricing page did not return content for us; the inbound product page lists no price.
- 6
Barracuda Email Protection
Barracuda Email Protection ranks sixth. It connects to Microsoft 365 or Google Workspace by API without MX changes and layers a multi-model engine called Barracuda IQ with account takeover detection and an explainer that describes detection decisions in plain language. A free trial and email threat scan lower the entry barrier. It is sold to a broad installed base, so deep tuning is less of the pitch.
Strong on
- Bailey Explainable AI describes why a message was flagged, which helps small teams justify blocks.
- A free trial and free Email Threat Scan let buyers test before any quote.
- Agentic clawback removes threats across mailboxes after delivery.
Weak on
- Plan tiers and prices sit behind a separate page and a configurator, not in the product text.
- Certifications were not stated on the product page; check the trust center before procurement.
Skip it if: Enterprises wanting a published price per mailbox or a vendor focused only on advanced BEC research. No prices are listed; a Build and Price tool and a under-50 or over-50 user filter replace them.
- 7
Check Point Harmony Email & Collaboration
Check Point Harmony Email & Collaboration is seventh. It deploys through an API without MX changes, can enforce inline from monitor mode, and runs ThreatCloud AI with more than 50 engines, extending to Teams, SharePoint, OneDrive and Slack. Its 2026 pitch adds protection against hijacked AI agents reading email. A security-suite company sells it, so the buyer often meets it inside a wider Check Point bundle.
Strong on
- Monitor mode through inline prevention can be switched on without changing MX records.
- Covers collaboration tools like Slack and Teams, not just mail.
- Two packages, Advanced Protect and Complete Protect, add data loss prevention in the upper tier.
Weak on
- No price is published for either package or the add-ons such as archiving and DMARC.
- Headline prevention rates are vendor figures, so test them on your own mail.
Skip it if: Teams who want a specialist email vendor and no other Check Point products in the contract. Pricing is a quote; the pricing page names Advanced Protect and Complete Protect packages without amounts.
- 8
Mimecast Advanced Email Security
Mimecast Advanced Email Security is eighth. The vendor offers both MX-based deployment, with inline inspection and continuity if the mail server fails, and an API option with no MX change, across Microsoft 365, Google Workspace and on-premises mail. Its AI and social-graph anomaly detection sit beside sandboxing and click-time protection. The portfolio is broad, spanning archive, DMARC and awareness training, which makes scoping the contract the hard part.
Strong on
- Offers both gateway and API deployment, covering Microsoft 365, Google Workspace and on-premises mail.
- Built-in continuity keeps mail flowing when the primary mail server fails.
- Integrations include CrowdStrike, Netskope and Palo Alto Networks Cortex XSOAR.
Weak on
- Plans are described as tailored and no prices appear on the product page.
- The product page did not state data center locations or certifications.
Skip it if: Small teams wanting a single email add-on without archive, awareness and other modules to scope. The product page points to tailored plans and lists no prices.
- 9
Proofpoint Core Email Protection
Proofpoint Core Email Protection ranks ninth because the biggest brands should not lead a ranking of tools buyers can still compare. It combines multi-model behavioral AI, sandboxing, click-time protection and an abuse-mailbox agent, deployable as a gateway or through Microsoft Graph with no MX change. The page claims deployment in about 48 hours. Its figures on threats blocked are the vendor's own, and the wider portfolio inflates contract scope.
Strong on
- Offers both a secure email gateway and an API deployment through Microsoft Graph.
- Threat Protection Workbench pulls email investigations into one view for analysts.
- The Satori agent handles messages that users report as suspicious.
Weak on
- No price is published, and the portfolio spans fraud defense, relay and data loss products.
- Detection claims such as 99.999% blocked are the vendor's own.
Skip it if: Small businesses without a security analyst who would manage a large product family. The product page links only to a how-to-buy section, with no price shown.
- 10
Microsoft Defender for Office 365
Microsoft Defender for Office 365 closes the ranking at tenth, only because it is the default every other tool here is measured against. It is the only product in this list with published prices, from $2.00 per user per month, and it protects Teams, SharePoint and OneDrive too. Plan 2 adds automated investigation and attack simulation. It protects Microsoft environments best, so Google Workspace shops gain little.
Strong on
- Plan 1 starts at $2.00 per user per month, the only published entry price in this ranking.
- Plan 2 adds automated investigation and response and cyberattack simulation training.
- Language model-based sentiment analysis is included in both plans, per the vendor.
Weak on
- Protects Microsoft 365 mail, Teams, SharePoint and OneDrive, not other mail platforms.
- The vendor's 99.99% accuracy claim is not tied to a plan or independently audited.
Skip it if: Companies on Google Workspace or those wanting a second vendor to cover Microsoft's blind spots. Annual subscription billed monthly per user; Plan 2 is $5.00 and the Defender Suite is $12.00, as of October 2026.
- 11
Darktrace / EMAIL
Darktrace / EMAIL ranks eleventh because the vendor publishes no price and the product leans on a wider platform. Darktrace says its models learn from each customer's own mail and users, not a shared cross-customer model, and it targets phishing, business email compromise and account takeover. Reasoning for decisions is shown and tuning is left to the security team. Buyers cannot compare cost without a sales call.
Strong on
- Learns from the customer's own organization, with no shared cross-customer model, per the vendor
- Shows its reasoning for decisions and lets security teams adjust tuning directly
- Identity response and security awareness training sit in the same platform
Weak on
- No list price is published, so budgeting requires a demo and quote
- The full benefit comes with other Darktrace modules, which widens the purchase
Skip it if: Small businesses wanting a published monthly price per mailbox or a basic filter without a sales process. No price is published; the page offers a demo request only, so cost comes from a quote.
How these AI email security software were judged
How well does AI email security catch business email compromise?
AI helps most where there is no malicious file to scan. Abnormal AI builds a baseline for each employee and vendor, IRONSCALES runs three named AI agents, and Libraesva pairs Semantic AI with Adaptive Trust AI to read intent and spot odd communication patterns. Check Point states more than 50 engines, and Microsoft describes language model-based sentiment analysis. Every catch rate in this ranking comes from the vendor. Run a pilot on your own mail for two weeks, count what each product caught that your current filter missed, and count false positives your helpdesk had to release.
What does AI email security cost per user per month?
Only Microsoft publishes numbers: Defender for Office 365 Plan 1 is $2.00 and Plan 2 is $5.00 per user per month, with the Defender Suite at $12.00, as of October 2026. Libraesva, IRONSCALES, Hornetsecurity, Barracuda, Check Point, Mimecast, Proofpoint, Abnormal AI and Egress sell by quote. IRONSCALES prices by plan from Email Essentials to Email Protect 360, and Check Point splits Advanced Protect from Complete Protect. Budget for add-ons too, since DMARC, archiving, account takeover protection and training are separate lines at several vendors.
Does an AI email security vendor read and train on your mail?
Every product here must read message content, so ask what leaves your tenant. Libraesva states its AI and sandbox run locally with no content shared and that Adaptive Trust AI never trains on customer content. Hornetsecurity states 12 regional data centers independent of Microsoft. Abnormal AI lists SOC 2 Type II and ISO 27001, with hosting and training terms behind a data protection addendum. Training terms were not checked for every vendor, so request the DPA, subprocessor list and a written model-training statement before signing.
How hard is it to switch email security vendors later?
Switching an API add-on is easy because you disconnect the integration and keep your mail platform. Switching a gateway means another MX change and a period of dual routing, as with Libraesva, Mimecast and Hornetsecurity, whose archive and backup modules hold historical mail you must export. Bundles raise the exit cost: Microsoft Defender sits inside licensing, and Proofpoint, Mimecast and Check Point sell adjacent products. Ask for a data export of quarantined mail and policy settings, and keep your DMARC records in your own DNS.
Which AI email security tool suits a 200-person company?
A 200-person company without a dedicated analyst needs fast setup and low tuning. IRONSCALES and Barracuda deploy by API, and Barracuda adds a free trial and plain-language explanations. A Microsoft 365 company wanting the lowest published cost starts with Defender Plan 1. Organizations with strict data residency look at Libraesva or Hornetsecurity. Proofpoint and Mimecast suit larger teams with analysts and mixed mail systems, where the broad portfolio justifies its scoping effort. Abnormal AI fits a team whose main loss is invoice and vendor fraud.
How to choose an AI email security platform in three steps
- List the fraud you actually receive. Pull three months of reported phishing and fraud from your helpdesk and sort it into credential links, malicious attachments, invoice fraud, executive impersonation and account takeover. Behavioral products such as Abnormal AI and IRONSCALES target the payload-free kinds, while gateways with sandboxes cover attachments. If most of your loss is a spoofed supplier asking for a changed bank account, ask each vendor to demonstrate how it detects vendor email compromise, not only how it blocks malware, and ask for a customer reference in your industry.
- Decide gateway or API before comparing vendors. A gateway such as Libraesva, Mimecast or Hornetsecurity needs an MX change and gives continuity, archive and pre-delivery filtering. An API product reads mailboxes through Microsoft Graph or Google APIs and removes mail after delivery. Many buyers keep Microsoft Defender as the baseline and add an API layer on top. Choose the model your team can actually support, then compare only vendors that offer it, because a mixed shortlist of gateways and add-ons makes every demo harder to score fairly.
- Run a two-week pilot with a scorecard. Ask two or three vendors for a free trial or scan, which Libraesva, IRONSCALES, Barracuda and Check Point list. Run them in monitor mode on real mailboxes and record threats caught that your current filter missed, legitimate mail wrongly flagged, hours spent releasing mail and remediation time. Get written pricing for your mailbox count before the pilot ends, since quote-only vendors can change terms once a trial has already shaped your workflow and your team is attached to the console.
Frequently asked questions
What is the best AI email security software in 2026?
Libraesva Email Security leads this ranking because it processes AI analysis inside the customer's environment and offers a 30-day trial. IRONSCALES is the pick for lean teams adding an API layer, and Microsoft Defender for Office 365 is the pick for Microsoft shops wanting a published price. Order reflects editorial judgment, not a benchmark.
Is Microsoft Defender for Office 365 enough on its own?
For many small companies the answer is yes, because Plan 1 at $2.00 per user per month covers email, Teams, SharePoint and OneDrive with anti-malware, link and QR code protection. Teams facing targeted invoice fraud often add an API product such as IRONSCALES or Abnormal AI. Judge it by a pilot that counts what Defender missed on your own mail.
Does AI email security need an MX record change?
It depends on the product. Libraesva, Hornetsecurity and Mimecast's gateway option route mail through the vendor first, so they need an MX change. IRONSCALES, Abnormal AI, Barracuda, Check Point and Proofpoint's API option state no MX change. Mimecast offers both, so confirm which mode the quote covers before comparing cost.
Which AI email security tools publish their prices?
Among the ten here, only Microsoft Defender for Office 365 publishes prices: $2.00 per user per month for Plan 1 and $5.00 for Plan 2 as of October 2026. The other nine use quotes, request forms or demos. Treat any third-party price list for them as unverified and ask for written pricing at your mailbox count.
Can I use AI email security with Google Workspace?
Yes, several support it. IRONSCALES, Abnormal AI, Barracuda, Check Point and Proofpoint list Google Workspace support, and Mimecast's environments include it. Microsoft Defender for Office 365 protects Microsoft 365 only, so a Google Workspace company needs another product. Confirm which Google features, such as Gmail only or Drive too, the quote covers.
Do these tools use my email to train their AI?
Training terms were not verified for most vendors here. Libraesva states Adaptive Trust AI never trains on customer content, and Abnormal AI refers buyers to its privacy guide and data protection addendum. For the rest, ask for a written statement and the subprocessor list. Do not assume that a trust center certification answers the training question.
Which tools suit managed service providers?
IRONSCALES describes a multi-tenant console with per-client policies and a partner program, and Hornetsecurity lists a 365 Multi Tenant Manager for MSPs. Barracuda lists an MSP Today 2026 product award. Compare per-tenant pricing, white-label options and remediation workload, because margin depends on how many reported emails your analysts still handle.
How do I test AI email security before buying?
Request a free trial or scan, which Libraesva, IRONSCALES, Barracuda and Check Point advertise, and run it in monitor mode on real mailboxes for two weeks. Count missed threats, false positives and remediation time against your current filter. Ask for pricing in writing at your mailbox count, because quote-only vendors do not publish rates.