Confluent Inc., a startup dedicated to commercializing the open-source Apache Kafka project, joined Silicon Valley’s unicorn club today after revealing that it has raised a late-stage $125 million round at a $2.5 billion valuation.

Sequoia Capital led the Series D investment with participation from two other prominent venture capital firms, Index Ventures and Benchmark. The round represents a doubling down on the $50 million they injected into Confluent two years ago as part of its Series C raise.

The Palo Alto, California-based startup was founded in 2014 by the engineers who led the internal LinkedIn project that would eventually become Kafka. The software is an event streaming platform that enables enterprises to transport massive volumes of data to, as well as between, their applications. It lends itself to everything from ingesting website traffic metrics to collecting soil measurements recorded by sensors in a far-flung field.

Kafka transports data with a high degree of reliability and low latency, a powerful combination that has made it a hit in the enterprise. J.P. Morgan Chase & Co, Lyft Inc. and Audi AG and are among the corporate giants that use the platform to manage how information flows through their internal systems.

“For companies built this way, their event streaming platform is very much the central nervous system through which the core events of their business flow, connecting all their systems and applications across diverse geographies and lines of business,” Confluent Chief Executive Jay Kreps (pictured) wrote in a blog post.

The rapid enterprise uptake of Kafka, coupled with the vital role it plays in adopters’ technology infrastructure, has presented abundant revenue opportunities for Confluent. The startup makes money by selling professional services and commercial tools aimed at making the event processing platform easier to use.

Confluent’s flagship offering is a Kafka distribution called the Confluent Platform. It includes extra reliability features, ready-to-use integrations with popular enterprise applications and advanced analytics tools. One of the standout capabilities is an engine for performing real-time analytics on data processed by Kafka.

The startup claims to have grown total subscription bookings by 350 percent in 2018. Sources told Forbes that the startup is now generating a $100 million in annual bookings, a major feat given the well-recorded challenges of making money off open-source technology.

“Confluent is the fastest-growing enterprise subscription company by revenue since launch that we have partnered with to date,” Sequoia partner Matt Miller said in a statement.

The new round could go a long way toward helping Confluent maintain this growth. In the past year, the startup more than doubled its headcount and marked several big product milestones, including the release of its Kafka distribution on Amazon Web Services. Confluent is likely to continue prioritizing the public cloud going forward given the current trends in enterprise technology spending.

Photo: Confluent