Sublime Security
8 known investors
Sublime Security is an AI-powered, programmable email security platform that detects, triages and adapts defenses against email attacks.
Also known as Sublime
Founders & leadership
Investors · 8
Also in the syndicate · 1
Valuation · disclosed
Disclosed eventsSource: SEC prospectus filings, and round valuations the company or its investors disclosed — follow each entry's link for the claim.
Company profile
researched Aug 2026Sublime Security develops a cloud email security platform that protects organizations against email-originated attacks such as phishing and business email compromise. The platform layers on top of Microsoft 365, Google Workspace or any IMAP mail server, copying incoming messages through journaling or Graph/Gmail APIs into its processing pipeline, where each message is parsed into a structured JSON representation called the Message Data Model. Security teams write detections in Sublime's Message Query Language, an SQL-like language covering email content, headers, attachments and metadata, and can move from ad-hoc threat hunting to permanent detection rules.
Detection combines several AI engines: natural language models assess business intent, urgency and sentiment to catch text-only business email compromise messages with no malicious link or attachment, while computer vision models identify spoofed logos, QR codes and obfuscated text in images. The company has since positioned itself as an agentic platform, adding an Autonomous Security Analyst that triages user-reported phishing, runs detonations, quarantines malicious mail and replies to users, and an Autonomous Detection Engineer that reviews missed attacks, drafts and tests new rules and submits them for approval. Teams can operate in a guided mode approving suggested rules or an advanced mode authoring custom logic and pushing it to production.
The company positions its approach against traditional "black-box" secure email gateways by emphasizing transparency, configurability and auditability of blocking decisions, and compares its intended market impact to the shift CrowdStrike drove in endpoint detection and response.
Founding story
Sublime Security was founded in 2019 by Josh Kamdjou, who serves as CEO, and Ian Thiel; Index Ventures identifies the two as the founding team.
Business model
B2B SaaS subscription priced by number of protected mailboxes, deployed either as a cloud service or as self-managed Docker containers for regulated customers requiring on-premises deployment. A free tier exists: the Core Platform can be self-hosted for free at any scale, and the first 100 inboxes are free in the hosted SaaS environment, with Sublime Enterprise as the paid offering. Cost structure includes cloud infrastructure and AI model inference.
Recurring subscription revenue from enterprise customers based on protected mailbox counts, with expansion as customers roll the platform out to additional business units and integrate it further into security operations workflows. The company reported 100% annual recurring revenue growth in the first half of 2025.
Traction
Total disclosed funding of $243.8M as of the October 2025 Series C. The customer base quadrupled between the Series A and the December 2024 Series B, and the company reported 100% ARR growth in the first half of 2025 with 100% enterprise customer retention since inception. Publicly named customers span technology, security, retail and energy sectors.
Latest developments
In October 2025 Sublime announced a $150M Series C led by Georgian, with new investors Avenir and 01A joining existing backers Index Ventures, IVP, Citi Ventures and Slow Ventures, at a reported post-money valuation of approximately $926M. The proceeds are directed at expanding its AI agent lineup, further platform development and international growth. Subsequent company announcements cite inclusion in the Rising in Cyber 2026 list and a Best Security Solution for Email win in the 2026 Security Awards.
▸Full profile — market position, technology, go-to-market, geography, history, risks & controversies
Market position
Competes in AI-native email security alongside Abnormal Security, Material Security and IRONSCALES, and against legacy secure email gateway incumbents Proofpoint and Mimecast as well as Microsoft's native Office 365 protections. Sublime differentiates on an open, customizable detection layer rather than closed detection systems. Sacra reports a post-money valuation of approximately $926M following the October 2025 Series C, versus Abnormal Security's reported $5B valuation and over $200M ARR.
Transparency and programmability: customers can read, modify and author detection rules in Message Query Language, audit every blocking decision, and self-host, in contrast to closed, one-size-fits-all detection systems. The open-source, MIT-licensed rule catalog draws community contributions, and agentic AI features aim to shorten the time from novel attack to deployed detection from vendor-dependent cycles to hours.
Technology
Message ingestion via journaling and Graph/Gmail APIs; a structured Message Data Model; the Message Query Language for writing detection rules; natural language models for intent, urgency and sentiment analysis to detect payload-free business email compromise; computer vision models for logo spoofing, QR codes and obfuscated image text; autonomous AI agents for triage and detection engineering; and integrations that extend detections into SIEM and SOAR tooling.
Go-to-market
Sells directly to enterprise security teams, with a free self-hosted Core Platform and a free 100-inbox hosted tier serving as entry points. An open-source component with MIT-licensed detection rules supports a community-driven development model in which over one-third of the default rule catalog comes from community contributions, functioning as a lead source. Colin Jones, formerly CRO at Wiz, joined as President in December 2024 to run go-to-market.
Enterprise security teams, including compliance-heavy industries that require auditable blocking decisions and on-premises deployment options. Named customers include Spotify, Reddit, Brex, Elastic, Benteler, Cribl, Snowflake, Zscaler, Anduril, Centrica, British Gas, SentinelOne, Compass and ASOS.
Geography
Headquartered in Washington, United States, with plans stated at the Series C to grow its global footprint. Named customers include organizations based in Europe such as Centrica, British Gas, Benteler and ASOS.
History
Founded in 2019. The company raised seed funding from investors including BoxGroup, followed by a $20M Series A led by Index Ventures, a $60M Series B led by IVP announced in December 2024 that brought total funding to $93.8M, and a $150M Series C led by Georgian announced in October 2025. In the first half of 2025 it shipped its first two AI agents, and it has been recognized in the Rising in Cyber 2026 list and with a Best Security Solution for Email award in the 2026 Security Awards.
Risks & controversies
The company operates in a crowded email security market against better-capitalized AI-native rivals such as Abnormal Security and entrenched incumbents Proofpoint, Mimecast and Microsoft, whose bundling of native Office 365 protection is described as a significant competitive moat. Its cost base is exposed to cloud infrastructure and AI model inference expenses.
Compiled by commissioned research from 4 cited public sources — announcements, filings, and press listed under research sources below.
Key figures
latest reportedCompany-reported or press-reported figures, each dated to when it was claimed — not independently audited.
Timeline · 6
launches, deals, and filingsSublime Security announced it won Best Security Solution for Email in the 2026 Security Awards.
Series C round led by Georgian with new investors Avenir and 01A and existing investors Index Ventures, IVP, Citi Ventures and Slow Ventures; proceeds earmarked for agentic AI capabilities and global expansion.
$150M source ↗
In the six months preceding the Series C, Sublime launched two AI agents: the Autonomous Security Analyst, which investigates and triages threats, and the Autonomous Detection Engineer, which deploys tailored detections against novel threats.
Series B led by IVP with participation from new investor Citi Ventures and existing investors Index Ventures, Decibel Partners and Slow Ventures, bringing total funding to $93.8M.
$60M source ↗
Colin Jones, previously Chief Revenue Officer at Wiz, joined Sublime Security as President to run go-to-market.
Dated company events from announcements, filings, and press; legal rows summarize public dockets and regulator releases.
In the news
▸Research sources · 4
primary sources listed
- Sublime Security Secures $60 Million in Series B Funding to Establish a New Standard in Email Securityprnewswire.com · web
4 public sources were cited for this profile; the first-party ones are listed here.
Frequently asked questions
- What does Sublime Security do?
- Sublime Security is an AI-powered, programmable email security platform that detects, triages and adapts defenses against email attacks.
- Who founded Sublime Security?
- Sublime Security was founded by Josh Kamdjou.
- Who are Sublime Security's investors?
- Sublime Security's investors include 01 Advisors, Avenir Growth Capital, Aviso Ventures, Decibel Partners, Index Ventures, IVP (Institutional Venture Partners), Slow Ventures.