omnischolar / crossref
Omnischolar Crossref: the reference metadata of any Crossref DOI, the works deposited with an ORCID, a bibliographic search - no key, in the polite pool with a mailto.
Requires
- php: >=8.2
- omnisense/omnischolar: ^1.0
- symfony/http-client: ^6.4|^7.0|^8.0
Requires (Dev)
- phpunit/phpunit: ^11.0
Suggests
None
Provides
None
Conflicts
None
Replaces
None
README
Crossref for omnisense/omnischolar: the reference
metadata of any work with a Crossref DOI - title, authors and their ORCIDs, journal or book,
volume, pages, publisher, ISBNs, licence, the citation count Crossref knows - the works deposited
with an ORCID, the works signed with a name, a bibliographic search. No key; with a mailto,
the calls go to Crossref's polite pool.
$crossref = (new CrossrefSourceFactory($http))->create(['mailto' => 'support@glitchr.io']); $crossref->work('10.1140/epjd/s10053-022-00549-6'); $crossref->works('0000-0002-9127-1687'); // deposited with that ORCID $crossref->works('Alain Aspect'); // signed with that name
omnischolar: sources: crossref: { factory: crossref, options: { mailto: 'support@glitchr.io' } }
The client is written directly on Symfony's HttpClient: the API is plain JSON, and a client library (renanbr/crossref-client) would add a dependency without removing code.
See docs/.
Install
composer require omnischolar/crossref
It brings the family's core, omnisense/omnischolar, and omnisense/contracts with it. No account and no key; a mailto of yours puts the calls in Crossref's polite pool (policy.json). $http is HttpClient::create() in plain PHP.
Usage policy
Declared as data in policy.json (read at https://www.crossref.org/documentation/retrieve-metadata/rest-api/access-and-authentication/ on 2026-11-10), and honoured on every request by the
core: a limit reached waits when its window ends within max_wait seconds, else the request is not
sent (Usage policies).
- Limits: 5 a second for single; 1 a second for list; at most 1 in flight.
- Licence: not stated; commercial use: allowed.
- Credit: not required.
- Needs: nothing.
- With a
mailto: the polite pool, 10 single records and 3 lists a second, 3 in flight (CrossrefSource::usagePolicy()).
Responsibility
This package is an independent, unofficial client: it is not affiliated with, endorsed by or sponsored by Crossref. It reaches their service on behalf of whoever runs it, and it does not redistribute their data beyond the short excerpts recorded as test fixtures. Its MIT licence covers this package's code only and grants no right to the service or to its data.
Whoever installs and runs this package is responsible for complying with the Crossref REST API's terms (REST API documentation), for obtaining whatever they require (an account, a key, a licence or subscription, an attribution or a citation, a rate limit to respect), and for any use made of what it returns. The authors publish it free of charge, make no commercial use of it, and accept no liability for how it is used (see LICENSE).
License: MIT since 2026-10-09; earlier versions remain published under LGPL-3.0-or-later.