Sublime Security, a Washington, D.C. startup selling a programmable email security platform for Microsoft 365 and Google Workspace, has attracted $60 million in new funding as investors continue to place big bets on the email security business.

Sublime said the new capital was provided by IVP, Citi Ventures, Index Ventures, Decibel Partners, and Slow Ventures and brings the total raised to $93.8 million.

The company says it has gained enterprise traction with its technology, which combines AI-driven detection with a programmable rules engine to protect against phishing, malware and targeted Business Email Compromise (BEC).

Sublime, which competes with a wide range of well-capitalized startups to secure cloud email pipelines, said its tools are being used by security teams to perform threat hunting, auto-triage user-reported emails, and customize actions like quarantining messages or inserting warning banners.

Since its Series A raise seven months ago, the company said it has quadrupled its customer base, adding major enterprise clients like Elastic, Benteler, and Cribl, alongside existing users such as Spotify, Reddit, and Brex. 

Sublime said its Core Platform can be self-hosted for free at any scale, and the first 100 inboxes are free in its SaaS environment.  

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