NDLTD Union Catalog

The Union Catalog aggregates descriptive metadata for electronic theses and dissertations (ETDs) contributed by participating repositories worldwide. It is operated on behalf of the Networked Digital Library of Theses and Dissertations (NDLTD), and it collects its records over the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH).

568,234 records from 498 repositories.

Looking for a thesis or dissertation? This site serves the catalog to machines. The Global ETD Search is the interface for people. Search there, and follow each result to its originating repository.

Open Global ETD Search

For harvesters, crawlers, and AI agents

The Union Catalog is built to be read by machines. Every interface is read-only and requires no registration or API key. The documentation covers each interface with working examples.

OAI-PMH harvesting
Harvest the whole catalog or one repository's set.
/oai-pmh/ Harvester guide
Search API
Query the aggregated metadata over HTTP. Responses are JSON.
https://search.dev.ndltd.org/api/search API reference
Item metadata
Every public record serves JSON and JSON-LD representations from its item URL.
https://search.dev.ndltd.org/etd/<repo>/<id> API reference
MCP endpoint
AI assistants can search the catalog over the Model Context Protocol.
https://search.dev.ndltd.org/mcp API reference
RSS
The most recently added records, newest first.
/rss/
Sitemaps
Crawlers start from the sitemap index on the search host.
https://search.dev.ndltd.org/sitemap.xml

See the Terms of Service. The about page records the catalog's history and stewardship.