Definition

DOI (Digital Object Identifier)

A permanent, unique identifier for a scholarly object (10.xxxx/…) that resolves to its current location — the stable way to cite and link research.

URLs rot; DOIs are maintained: publishers register them (mostly via Crossref, or DataCite for datasets) and update the redirect when content moves. Appending the DOI to https://doi.org/ always reaches the object, which is why modern citation styles require it.

DOIs also power research infrastructure — citation databases, reference managers, and metadata lookup all key on them. Datasets, software, preprints, and even peer reviews get DOIs now, making them citable first-class outputs.