Organizations using Office 365 and G Suite turn to GreatHorn to protect against today’s greatest cybersecurity threats—targeted phishing attacks, business email compromise, malware and ransomware.


Cloud email calls for cloud-native email security. 

Office 365 and G Suite require a modern, cloud native email security solution to protect against advanced threats, which legacy email gateway technology just isn’t designed to catch. Only GreatHorn delivers a next generation email security platform purpose-built for cloud-based communications systems.

Built on a foundation of machine learning and automation, GreatHorn delivers the industry’s most effective and comprehensive email security solution, and can be deployed and operational in less than 5 minutes. With its proprietary dataset built from hundreds of millions of uniquely analyzed threats, GreatHorn combines the intelligence, fidelity and precision necessary to prevent attacks from becoming breaches.


We provide comprehensive protection against email-based threats.

Email continues to be the #1 attack vector and your employees will click phishing links, no matter the amount of security training.

Only GreatHorn is effective at protecting against targeted phishing, socially engineered attacks, malware and ransomware at the endpoint so they don’t progress into organizational attacks.

We disrupt cyber attacks — not your email performance.

GreatHorn delivers email security without requiring changes to MX records or mail flow. That means no performance delays, delivery risk or downtime.

Improve your security without impacting your end user’s email experience or productivity.

We integrate easily into your cloud email environment and deploy in under 5 minutes.

GreatHorn is cloud native and integrates seamlessly with Office 365 and G Suite without the need for agents or plugins. The solution provides universal protection across mail clients and devices – desktop and mobile.

GreatHorn is easy to set up and provides ultra-fast time to value. Out-of-the-box policies provide immediate protection from day one.

We save you a lot of time.

GreatHorn’s automated and configurable response actions reduce the time and effort spent by IT and security teams identifying and responding to suspicious emails by more than 80 percent.

GreatHorn helps you rapidly meet your email security requirements without adding complexity.

We provide post-delivery threat remediation and response.

Not every malicious email has readily apparent indicators of compromise. Some contain links or attachments that are altered only after they reach a user’s inbox.

Only GreatHorn is able to take action on emails — indefinitely — after they have arrived in your end users’ mailboxes.

We’re building a powerful community with shared intelligence.

When you choose GreatHorn, you become part of a growing community of organizations that benefit from shared threat intelligence.

With real-time intelligence and analysis from our community of cloud email users and other sources, GreatHorn will alert your organization to emergent threats before they reach your environment.


Incredible organizations from startups to Fortune 500 companies trust GreatHorn.


GreatHorn is proudly backed by: