Tessian

What Tessian does

Tessian is a UK-based artificial intelligence security company that developed a Human Layer Security platform to detect and prevent security threats caused by human error. The company's core technology applies machine learning and natural language processing to analyze email communications, identifying phishing attacks, misdirected emails, social engineering attempts, and data exfiltration. Its proprietary behavioral and dynamic detection capabilities form the technical foundation for products including Core Email Protection (deployed via API or gateway) and Adaptive Email DLP, both of which are now integrated into Proofpoint's email security portfolio following acquisition.

The company served approximately 350 global enterprise customers across financial services, healthcare, and general enterprise segments, addressing pain points including regulatory compliance (HIPAA, financial regulations), accidental and intentional data loss, and business email compromise. Tessian's go-to-market relied on enterprise field sales with quote-based pricing for subscription recurring contracts. The company maintained headquarters in London and a regional office in San Francisco to support North American operations. Tessian raised over $120 million across multiple funding rounds from investors including Sequoia Capital, Accel, Balderton Capital, March Capital, Okta Ventures, and Citi Ventures, achieving a $500 million post-money valuation at its Series C in May 2021.

Following acquisition by Proofpoint, Tessian's technology has been integrated into the parent company's broader email security and data loss prevention product suite, with distribution now extending through Proofpoint's channel partner network, technology alliance partners, and MSP partners. The Tessian brand has been subsumed under Proofpoint, and the standalone company no longer operates as an independent entity.

Name

Tessian

Legal name

Tessian Ltd.

Website

https://tessian.com

Company type

Private

Founded year

2017

Operating status

Acquired

Headcount range

101–250 employees

Short description

Tessian is a UK-based AI security company that built machine learning-powered human layer security to detect phishing, data exfiltration, and social engineering attacks in enterprise email. It served approximately 350 global enterprise customers before being acquired by Proofpoint.

Ownership category

akta.pro rank

Product category

Email and Human Layer Security Software

NAICS

Software Publishers (5132)

SIC

Services-Computer Programming, Data Processing, Etc. (7370)

akta.pro primary industry

Responsible AI, Security & Privacy Platforms (Safety, Guardrails, PII) (HDAEANAG)

akta.pro secondary industries

Endpoint Deception & Anti-Ransomware (HDADAEAL), Endpoint, Email & Web Safe-Use Practices Training (EDABAGAF), Identity, Fraud & Insurance-Specific RegTech Platforms (FSAGAGAJ)

Keywords

• Human layer security
• Email security software
• Data loss prevention
• Phishing protection
• Insider threat management

Headquarters

HQ city

London

HQ country

United Kingdom

HQ region

Europe

Offices2 records

Markets served

GTM type

B2B

Offering type

Software

Cost components

Personnel, Technology or R&D, Marketing or Sales, Operations, Infrastructure

Revenue model

1. Enterprise Security Platform Subscription: Subscription-based security platform providing ongoing threat protection and detection services for enterprise customers

Go-to-market motion2 records

Distribution channels4 records

Marketing channels7 records

Core offering

Tessian (now Proofpoint) sells an AI-powered human layer security platform that uses machine learning to detect and prevent email-borne threats caused by human error. Core offerings include Core Email Protection (via API or gateway), Adaptive Email DLP, Enterprise DLP, Email Fraud Defense, Account Takeover Protection, Insider Threat Management, and ZenGuide security awareness training, all targeted at large enterprise customers.

Product overview

Tessian, now part of Proofpoint, offers a comprehensive AI-powered human layer security platform. The core offering is Core Email Protection, which provides threat protection via API or gateway with AI-powered detection capabilities. The platform includes multiple integrated modules: Adaptive Email DLP and Enterprise DLP for data loss prevention, Email Fraud Defense for brand protection, Account Takeover Protection for identity security, Insider Threat Management for behavioral monitoring, and ZenGuide for security awareness training. The platform is powered by Proofpoint Nexus and Proofpoint Zen platforms that leverage advanced AI and threat intelligence to detect threats and protect against human error-related security risks including phishing, data exfiltration, and social engineering attacks. The company serves approximately 350 global customers and has expanded its solutions beyond email to messaging and web platforms.

Differentiator

Problem solved

Functional benefit

Products and services

• Core Email Protection Industry-leading threat protection delivered via API or gateway, providing comprehensive defenses against the human layer of risk with AI-powered detection for phishing, BEC, and social engineering threats. Targeted at enterprise security teams.
• Adaptive Email DLP Prevents misdirected emails and hidden data exfiltration by analyzing email content and recipient patterns to stop accidental and intentional data loss. For enterprise security and compliance teams.
• Enterprise DLP Enterprise-grade data loss prevention that prevents data loss across email, cloud, and endpoints using AI-powered behavioral analysis. For organizations needing unified DLP across channels.
• Email Fraud Defense Protects brand reputation, increases email deliverability, and identifies lookalike domains to prevent email fraud. For enterprises and brands needing email authentication and anti-fraud.
• ZenGuide Targeted, risk-based security awareness training platform that helps users identify, resist, and report cyber threats. For enterprise security awareness and training programs.
• Account Takeover Protection Detects, investigates, and responds to account takeovers to protect organizational security. For enterprise identity and access security teams.
• Insider Threat Management Provides visibility into risky behavior by careless, malicious, and compromised users to prevent insider threats. For security operations and insider risk teams.
• Proofpoint Nexus Advanced AI and threat intelligence platform that detects threats and assesses data risk across organizational communications. For enterprise security teams leveraging AI-driven detection.
• Proofpoint Zen Integrated control points platform that protects people and data anywhere across email and collaboration channels. For enterprises needing unified human-centric security.

Quantifiable outcome

• 65% of data loss incidents result from misdirected email
• +1 more outcomes

Segments3 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

Yes

API docs

API detail

Core technology

AI maturity

App detail

AI capability6 records

Feature3 records

Partnerships

One partnership is on record.

• ProofpointcoreStrategic or Co-development PartnerProofpoint acquired Tessian in late 2024/early 2025, integrating Tessian's AI-powered behavioral and dynamic detection technology into Proofpoint's email security platform. Tessian is now Proofpoint, with Tessian technology becoming part of Proofpoint Core Email Protection and Adaptive Email DLP products.

Scale indicators3 records

Recent moves6 records

Expansion highlights6 records

Broad incumbents

• Proofpoint: Proofpoint is Tessian's parent company post-acquisition and a leading email security, DLP, and human-layer security platform. Overlap is direct and substantial across Core Email Protection, Adaptive Email DLP, and insider threat — making it both a parent and the most relevant incumbent peer.
• Microsoft Defender for Office 365: Microsoft Defender for Office 365 is the default email security layer bundled with Microsoft 365 and competes directly with Tessian's Core Email Protection and phishing defense. It is a broad incumbent that pressures Tessian's differentiation and pricing across the enterprise installed base.
• Cisco Secure Email (formerly IronPort): Cisco's Secure Email portfolio provides enterprise email threat defense and DLP at scale. As a broad incumbent security vendor, it competes with Tessian/Proofpoint for the same enterprise email security budget and overlaps on phishing and data loss prevention.

Direct peers

• Mimecast: Mimecast is a direct competitor in enterprise email security, DLP, and threat protection. Both companies target enterprise customers with subscription-based email defense platforms addressing phishing, impersonation, and data loss — closely aligned business models and customer bases.
• Abnormal Security: Abnormal Security is an AI-native email security platform focused on behavioral analysis to stop phishing, BEC, and account takeover. It is one of the closest direct competitors to Tessian's behavioral detection approach, targeting the same enterprise buyer with similar ML-driven methodology.
• KnowBe4: KnowBe4 is a security awareness and human risk management platform (now encompassing Egress for email DLP). It is a direct peer to Tessian's ZenGuide awareness training and Adaptive Email DLP modules, and competes for the same people-centric security budget.
• Cofense: Cofense specializes in phishing detection, reporting, and response — closely aligned with Tessian's phishing and social engineering defense capabilities and targeting enterprise security operations teams.
• Avanan: Avanan (acquired by Check Point) is an AI-driven email and collaboration security platform protecting against phishing, account takeover, and data loss in cloud email — directly comparable to Tessian's enterprise email security and DLP functionality.

Emerging players

• IRONSCALES: IRONSCALES is an AI-driven email security and phishing defense platform with self-learning threat detection. It overlaps with Tessian's social engineering and phishing protection capabilities and serves a similar enterprise customer base.
• SlashNext: SlashNext uses AI to detect phishing, BEC, and social engineering attacks across email and other channels. It is an emerging AI-native peer with overlapping behavioral detection methodology and enterprise go-to-market.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat4 records

Key risks5 records

Key highlights6 records

Customer concentration

• Xx.com/tessian
• Facebookfacebook.com/TessianOfficial
• LinkedInlinkedin.com/company/tessian

Revenue estimate

Valuation estimate

Number of profiles

Profiles10 records

Funding overview

Funding rounds10 records

Investors18 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Tessian