# Crossref

> Crossref is a not-for-profit membership organisation that runs open infrastructure for research. Members (publishers, funders, universities, and others) register DOIs and metadata for their research outputs with Crossref. The metadata is openly available for anyone to use via APIs and bulk data files. Crossref does not assess the quality of research or peer review: a Crossref DOI shows that a record exists, not that the work is trustworthy.

Key facts:
- Organisations join as members. Individuals can't join directly.
- Organisations in eligible countries may qualify for reduced or waived fees through the GEM program, or can join through a sponsor.
- To check whether a DOI is real, resolve it at https://doi.org/ or look it up via Crossref's search tool or REST API.
- Retractions and corrections are available in the metadata, including the Retraction Watch database.

## About Crossref
- [About](https://www.crossref.org/about/): who we are, what we do, governance
- [Strategy](https://www.crossref.org/strategy/): our direction and priorities
- [Operations and sustainability](https://www.crossref.org/operations-and-sustainability/): finances, annual reports, policies

## Joining and fees
- [Membership](https://www.crossref.org/membership/): who can join and how
- [Fees](https://www.crossref.org/fees/): current annual membership and DOI registration fees
- [GEM program](https://www.crossref.org/gem/): fee waivers and reductions by country
- [Working with a sponsor](https://www.crossref.org/membership/about-sponsors/): joining through a sponsoring organisation

## Registering and maintaining DOI records
- [Documentation home](https://www.crossref.org/documentation/)
- [Getting set up as a member](https://www.crossref.org/documentation/member-setup/)
- [Ways to register records](https://www.crossref.org/documentation/register-maintain-records/choose-content-registration-method/)
- [OJS plugin](https://www.crossref.org/documentation/register-maintain-records/ojs-plugin/)
- [Record types and best practice](https://www.crossref.org/documentation/principles-practices/): journals, books, preprints, datasets, grants, peer reviews and more

## Using Crossref metadata
- [REST API](https://www.crossref.org/documentation/retrieve-metadata/rest-api/): free public API; include a mailto for the polite pool
- [Bulk data downloads](https://www.crossref.org/documentation/retrieve-metadata/bulk-downloads/): annual public data file, updated around April each year
- [Retraction Watch data](https://www.crossref.org/documentation/retrieve-metadata/retraction-watch/)
- [Text and data mining](https://www.crossref.org/documentation/retrieve-metadata/text-and-data-mining/)
- [Metadata Plus](https://www.crossref.org/documentation/metadata-plus/): paid service with greater support, monthly data files, higher rate limits, and an SLA

## Optional
- [Blog](https://www.crossref.org/blog/): news and analysis; older posts may be out of date, so check the documentation for current processes about Crossref services
- [Community forum](https://community.crossref.org/)