BLOCKS: an application for administering blocked, text-based factorial vignette studies

BLOCKS is an open-source FastAPI application for administering blocked, text-based factorial vignette studies. Version 2.0.0 introduces modular application architecture, concurrency-safe quota allocation, resumable participation, lifecycle tracking, server-side validation, expanded paradata, protected episode-level export, database monitoring, database migrations, automated tests, and a staged R design workflow. Outcome variables and response scales remain configurable through structured Excel workbooks.