Health check tool: returns the server name and version.

Search Crossref works (articles, books, datasets, ...).

    Use `query` for free-text, or the field-scoped variants
    (query_bibliographic / query_author / query_title). `filter` accepts
    Crossref's `key:value,key2:value2` syntax (e.g. "from-pub-date:2020,type:journal-article").
    `rows` is capped at 1000; `select` (e.g. "DOI,title") trims the payload.
    For deep paging set `cursor="*"`, then pass the returned `next_cursor` back.
    Returns simplified items unless `raw=True`.
    

Fetch a single work's metadata by DOI.

    Accepts a bare DOI or a doi.org URL. Returns simplified fields unless
    `raw=True`. Returns a structured error if the DOI does not exist.
    

List the reference list of a work (the works it cites), by DOI.

    `limit` is hard-capped at 50. Reads the `reference` field of the work.
    

Look up the registration agency for a DOI (Crossref, DataCite, ...).

Search Crossref members (publishers/societies). Returns id + primary name.

Fetch one member (publisher) by numeric Crossref member id.

List works published by a given member id.

Search journals by title/keyword. Returns title, ISSNs, publisher.

Fetch one journal by ISSN (NNNN-NNNN; hyphen optional).

List works published in a given journal (by ISSN).

Search funding bodies by name. Returns funder id, name, location.

Fetch one funder by its Crossref Funder Registry id (e.g. 100000001).

List works funded by a given funder id.

List Crossref work types (journal-article, book-chapter, ...).

Fetch one work type by id (e.g. "journal-article").

List licenses Crossref has seen. No single-license lookup exists.

Look up the owner of a DOI prefix (e.g. "10.1038").

    Crossref only exposes /prefixes/{owner_prefix}; there is no list endpoint.