Examples
Worked examples
- Is an instance
An institutional repository running DSpace that exposes an OAI-PMH endpoint, allowing a national aggregator to harvest its metadata automatically.
- Is an instance
A subject repository whose records are harvested by a discovery service via OAI-PMH rather than through a custom API.
Counter-examples
Looks similar, but isn't
- Not an instance
A repository that only offers a web search interface with no OAI-PMH (or equivalent structured harvesting) endpoint is not an open archive in this technical sense, even if its content is freely readable.
Editorial commentary
An open archive is a repository that exposes its metadata using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH), a standard interoperability protocol that lets external services, such as aggregators, discovery layers, and search indexes, systematically harvest a repository’s item-level metadata rather than crawling its web pages. OAI-PMH compliance is what makes an open archive machine-discoverable at scale: an aggregator can pull structured records from every OAI-PMH-compliant repository it knows about, rather than needing a bespoke integration with each one.
“Open” here refers to open metadata interoperability, not necessarily open access to the full text: an open archive’s records are harvestable even if some of the underlying content is embargoed or restricted. In practice, most repositories used for green open access, including institutional repositories and subject repositories, are built on repository software (DSpace, EPrints, Invenio, and similar) that supports OAI-PMH by default, so the terms are often used loosely as if interchangeable, but a repository that does not expose OAI-PMH is not, strictly, an open archive.
Machine-readable encodings
Use in your systems
<role vocab="credit"
vocab-identifier="https://casrai.org/dictionary/"
vocab-term="Open archive"
vocab-term-identifier="https://casrai.org/dictionary/term/open-archive" />{
"@context": "https://schema.org",
"@type": "DefinedTerm",
"@id": "https://casrai.org/dictionary/term/open-archive",
"name": "Open archive",
"identifier": "https://casrai.org/dictionary/term/open-archive",
"description": "A repository that is compliant with the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) and therefore facilitates the sharing of metadata for a variety of purposes, most notably the compilation tasks performed by aggregator databases.",
"inDefinedTermSet": "https://casrai.org/dictionary/domain/data-infrastructure#set",
"url": "https://casrai.org/dictionary/term/open-archive",
"sameAs": [],
"license": "https://creativecommons.org/licenses/by/4.0/",
"publisher": {
"@id": "https://casrai.org/#organization"
},
"dateModified": "2026-08-17T01:54:04",
"inLanguage": "en"
}
