Filigran

Filigran is the company behind OpenCTI and OpenBAS, two widely deployed open-source security projects that it has turned into a commercial suite. OpenCTI structures, correlates, and enriches threat intelligence pulled from commercial feeds, internal telemetry, and open-source sources into a single graph-based knowledge base analysts can query and act on. OpenBAS is a breach and attack simulation engine that runs realistic adversary scenarios, informed by that same threat intelligence, to test whether an organization’s controls actually catch what they are supposed to catch.

The Paris-based company was founded in 2022 by Samuel Hassine and Julien Richard, building on threat intelligence tooling Hassine had previously developed. Filigran has grown quickly since: a $16 million round in early 2024, a $35 million Series B in October 2024, and a $58 million Series C in October 2025 led by Eurazeo with participation from Insight Partners, Accel, and Deutsche Telekom’s T.Capital, bringing cumulative funding to roughly $110 million. Headcount has grown alongside the funding, from roughly 160 to over 260 employees within a year.

What differentiates Filigran from most commercial threat intel vendors is the open-source distribution model underneath it: OpenCTI alone is used by more than 6,000 public and private sector organizations, including government CERTs and large enterprises, which gives Filigran both a large top-of-funnel and a connector ecosystem that commercial-only competitors have to build from scratch. The company monetizes through enterprise features, hosting, and support on top of the free open-source core, plus OpenBAS for organizations that want to validate their intelligence rather than just collect it.

Filigran’s rapid, well-documented funding trajectory and broad organic open-source adoption are unusually well substantiated for a company this young, which is a meaningful point in its favor relative to threat intel vendors that rely mostly on marketing claims of adoption.