API-BASED EMAIL SECURITY 

API-Based Email Security That Catches What Microsoft Misses

Stop threats that reach the inbox with multi-model, intent-based AI protection. Deploy in 48 hours.

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SEAMLESS INTEGRATION

Close security gaps with AI-powered API protection

API-based email security integrates directly with Microsoft 365 to stop sophisticated attacks that bypass Microsoft Defender. Combined with advanced multi-model AI for intent-based detection, it automatically removes threats from the inbox before users can act on them.

Catch what Microsoft misses

Understand intent, not just unusual behavior, to detect novel threats that evade Microsoft's native filtering.

Get complete, automated explainability

Map what was detected, who was targeted, and how the attack unfolded with every detection.

Roll out without disruption

Go live in as little as 48 hours with zero MX changes, zero mail flow changes, and zero downtime.

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AI-POWERED EMAIL THREATS

AI has changed what a novel attack looks like

Today’s most effective email threats use personalized, AI-generated lures with no known fingerprints. With nothing for detection technologies based on known indicators to match against, these attacks can exploit gaps in Microsoft 365’s native defenses to reach inboxes hundreds of times per day.

27 %

of malicious emails bypass Microsoft's native filtering

Proofpoint, 2026.

46 %

year-over-year growth in email threats

Proofpoint, 2026.

4.5 X

higher click rate for AI-generated vs. traditional phishing

Proofpoint, 2026.

Core Email Protection UI Dashboard with play button

INDUSTRY-LEADING PROTECTION 

Stop email threats the moment they appear

Proofpoint Core Email Protection API detects and blocks advanced threats using global intelligence, not just tenant-local signals, to inform every verdict. The industry’s largest email telemetry network, spanning 3.4 million customers, approximately 200 named threat actors, and more than 9,000 active campaigns, helps identify novel attacks before they reach your organization.

Every year, Core Email Protection stops:

  • 2.2B phishing attempts
  • 369M malware attacks 
  • 138M BEC attacks
  • 395M TOAD attacks 
See Core Email Protection in Action

Novel Threat Detection

Detect 31% more novel threats than with other email security providers, including zero-day campaigns.

18-Minute Global Propagation

Get protected within 18 minutes when Proofpoint Nexus AI detects a new threat anywhere in the world.

Measurablew Risk Reduction

Reduce the risk of a major breach by up to 75% when layered on Microsoft 365 native protection.

Independently Benchmarked

Gain proven post-delivery protection that outperformed every other API vendor in Microsoft’s 2026 benchmark.

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Proofpoint Nexus AI dashboard with play button overlay

INTENT AND CONTEXT

Protect based on message intent

Core Email Protection API uses multi-model Nexus AI to detect email threats based on message intent, not just deviations from normal behavior. It analyzes who is communicating, what they’re asking, and why to uncover threats that behavioral analysis overlooks, blocking 99.999% of threats with an industry-best 1:19.7 million false-positive rate.

See Nexus AI In Action

Intent-Based Detection

Detect threats based on what a message is trying to accomplish, not just unusual behavior patterns.

Dynamic Payload Detonation

Inspect what links and files actually do, stopping attacks that pass basic behavioral checks.

Nexus Evaluation Engine

Get clear verdicts in milliseconds, and escalate suspicious messages for deeper analysis.

QR, OCR, and Visual Analysis

Parse QR code lures, images, and brand impersonation techniques that text-only analysis can miss.

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EXPLAINABILITY

Get the whole story behind every detection, not just an alert

Proofpoint Threat Protection Workbench is the console for Core Email Protection API. Analysts can see the full reasoning behind every Nexus AI verdict—sender patterns, detonation results, and model confidence—for complete explainability, instead of an opaque black box score.

Threat Interaction Map

Map what was detected, who was targeted, how the attack unfolded, and any related consequences, all in one view.

Threat Insights Reporting

Generate reports on attack volume, your most targeted users, and your exposure compared to industry peers.

Abuse Mailbox Automation

Auto-remediate most user-reported email so analysts can stay focused on what needs real review.

Fast, Secure Threat Response

Automatically move condemned mail to a hidden location users cannot search for or open.

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Close the pre-delivery gap

Add Proofpoint Secure Email Gateway for pre-delivery protection on the same detection engine, in the same console. Cover the full email lifecycle, with nothing duplicated and nothing missed.

Read our SEG + API e-book
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UNIFIED PLATFORM

Extend industry-leading protection beyond the inbox

Today, 99% of organizations face account takeover attempts. Scale Core Email Protection's detection architecture across every channel attackers exploit with Proofpoint Collaboration Security Prime, and investigate and remediate it all from a single console.

Account Takeover Protection

Automatically revoke sessions, malicious mailbox rules, OAuth access, and unauthorized file sharing.

Supplier Threat Protection

Identify compromised supplier accounts before an attack from a trusted domain reaches users.

Messaging Protection

Extend the same detection into chat and SaaS apps, and correlate multi-channel threat campaigns.

Secure Email Relay

Stop attackers from abusing your domain through unmanaged application and vendor email.

AI ThreatFlip Workflow

Turn real phishing caught by the API into safe, ready-to-run employee training simulations.

Email Fraud Defense

Block attackers from sending as your brand, protecting customers, partners and your reputation.

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Even Microsoft's own benchmark backs it up 

Proofpoint caught the most post-delivery malicious mail out of any vendor in Microsoft's 2026 benchmark of API email security tools. 

See the benchmark See how we compare

Why Proofpoint

Core Email Protection API vs. behavioral-only API tools

CapabilityBehavioral-only API toolsCore Email Protection API
Detection ApproachTypically built around behavioral anomaly detection alone, measuring messages against a baseline of normal patternsAnalyzes intent, relationships, and content with multi-model AI to uncover risk that looks legitimate through a behavioral lens alone
Payload inspectionNo equivalent dynamic sandboxing; payloads are inferred from sender behavior, not detonated and observedUses built-in dynamic URL and attachment detonation to inspect links or files for what they actually do
Threat intelligenceUses tenant-local signals drawn from a single organization's mail historyScans 2.37T emails and 19.5T URLs yearly across 3.4M customers, with new detections propagated worldwide in 18 minutes
RemediationOften moves mail to a folder the user can still open, so exposure is documented rather than closedMoves messages to a hidden location the user can't search for or open, blocking access entirely
ExplainabilityTypically one behavioral signal, with no further explanation given to analystsShows reasoning behind every verdict: sender pattern, detonation result, and model confidence, with a full Threat Interaction Map
Coverage beyond emailEmail-only point tool, with no path to pre-delivery protectionExtends to account takeover, supplier risk, messaging, and security awareness training, with SEG for pre-delivery protection

Request a Demo

Catch what Microsoft Defender misses with Core Email Protection API. Request a demo to see it in action.

Recommended for You

Resources to strengthen your email security

Core Email Protection API Solution Brief

Read the solution brief

Proofpoint vs. Abnormal Security

Compare solutions

Complete Coverage with SEG and API

Read the e-book

Check out all our industry insights, reports, and video resources

See all resources
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Frequently Asked Questions

API-based email security is a layer that connects directly to a cloud email platform like Microsoft 365, rather than sitting in the mail path. It inspects messages after native filtering delivers them and removes malicious mail from the mailbox, with no MX record or mail-flow changes required. See our full glossary entry for a deeper technical breakdown: What Is API-Based Email Security?

Proofpoint aggregate proof-of-concept data shows Microsoft's native filtering misses 27% of malicious mail on average. That residual concentrates in novel, AI-generated attacks with no known fingerprint to match against. An API-based layer adds post-delivery detection on top of Microsoft 365 without replacing it. 

A SEG blocks threats before delivery and requires MX record changes to route mail through it. API-based email security works after delivery, detecting and removing malicious messages already in the mailbox with no mail-flow changes. Proofpoint runs both on the same detection engine, so organizations can start with API and add pre-delivery blocking later.

No. Proofpoint Core Email Protection API connects to Microsoft 365 through an API integration, so there are no MX or mail-flow changes, no migration project, and no downtime. Deployment can go live in as little as 48 hours. 

Most native and gateway filtering matches messages against known indicators: sender reputation, known-bad links, prior attack signatures. AI-generated lures with no prior fingerprint have nothing to match against, so they pass behavioral and reputation-based checks. Proofpoint's multi-model Nexus AI instead evaluates both behavioral anomalies and intent (what a message is trying to accomplish) to catch these before they're actioned.

Proofpoint Core Email Protection API moves condemned mail to a hidden location the user can't search for or open, ending access rather than just relocating it to a folder they can still reach. Most user-reported email is also auto-remediated through the Abuse Mailbox, so analysts focus only on what needs real review.