Fennel AI

Fennel is a machine learning feature platform founded in 2021 by former Meta and Microsoft engineers, raising $9M to build a unified system for real-time and batch feature computation. The platform allows ML engineers to define feature pipelines once and have Fennel automatically handle both real-time serving and historical backfill for training dataset generation, ensuring point-in-time correctness so that training data accurately reflects what would have been known at inference time. This eliminates a major source of training-serving skew in production ML systems. Fennel integrates with Python, supports streaming sources like Kafka alongside batch sources, and provides an SDK for defining feature transformations with strong typing and testing support. The company serves ML teams building production systems where feature correctness is critical for model reliability, including financial services, e-commerce, and recommendation systems. Fennel competes with Tecton and Chalk in the feature store market while focusing on the correctness guarantees and Python developer experience that reduce bugs in production ML systems. The platform also handles feature discovery and sharing across teams to reduce duplicate feature development work.