Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with marked inter-individual heterogeneity in trajectories and outcomes. Despite antifibrotic therapies, reliable risk stratification in routine practice remains suboptimal. OPEN-IPF is a multicentre retrospective observational cohort study designed to build a harmonised real-world dataset across Italian IPF referral centres to enable the development and external validation of machine-learning (ML) models predicting clinically relevant outcomes.