Definition
An open access journal is an academic journal that makes all published articles freely available online to any reader, without subscription fees, registration requirements, or access barriers. Readers anywhere in the world can download, read, and (depending on the license) share the articles at no cost.
Open access publishing contrasts with subscription publishing, where libraries and institutions pay annual fees to access journal content, and individual readers without institutional access pay per-article fees.
Open Access Models
Gold open access — The final published version (Version of Record) is freely available on the journal's website immediately upon publication. The journal may charge an Article Processing Charge (APC) to authors to cover publishing costs.
Diamond open access — Gold open access with no APC. The journal is funded by institutions, societies, or grants. Authors pay nothing; readers pay nothing.
Green open access — Authors self-archive a preprint or accepted manuscript in a repository (arXiv, PubMed Central, institutional repository). The journal may still have a subscription paywall for the Version of Record.
Hybrid open access — A subscription journal that allows individual articles to be made open access, typically for an additional APC.