# Crossref

> Scholarly works for Worldwide. Access: Public API. Terms checked November 2, 2026.

- Slug: crossref
- Page: https://api.lineage.rexstjohn.com/sources/crossref
- JSON: https://api.lineage.rexstjohn.com/v1/sources/crossref
- Records: Scholarly works
- Places: Worldwide
- Years: Not stated by the source
- Access method: api
- Key required: no
- Rate limit: Public pool: rate 5, concurrency 1. Polite pool (a mailto parameter or contact in the User-Agent): rate 10, concurrency 3. The API answers with x-rate-limit-limit and x-rate-limit-interval headers (3 per 1 s on the polite pool when checked).
- Status: live
- Review: verified, checked by hand on 2026-11-02
- Homepage: https://www.crossref.org/
- API docs: https://www.crossref.org/documentation/retrieve-metadata/rest-api/
- Terms: https://www.crossref.org/documentation/retrieve-metadata/rest-api/access-and-authentication/

## Notes

DOI metadata for journal articles, books and dissertations, with author affiliations where the publisher deposited them. No key. Lineage joins the polite pool by sending mailto (LINEAGE_CONTACT_EMAIL) as a parameter and in the User-Agent, spaces calls 400 ms apart per instance, caches responses 6 hours as the tips page asks, and backs off on 429. Crossref treats bibliographic metadata as facts with no reuse restriction; abstracts can carry the publisher's copyright, so Lineage does not request them. api.crossref.org serves no robots.txt (404).

## Evidence

- https://www.crossref.org/documentation/retrieve-metadata/rest-api/
- https://www.crossref.org/documentation/retrieve-metadata/rest-api/access-and-authentication/
- https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/

## Status

Live at the last check, 2026-11-03 04:33 UTC. HTTP 200 in 373 ms. One check a day.

This file describes a catalog entry only.