Crossref / Journal by ISSN with DOI counts

One journal by ISSN: title, publisher, subjects, both ISSNs, DOI counts (total, current, backfile), coverage percentages (abstracts, ORCIDs, references, funders, licenses) and DOIs registered per year. An unknown ISSN answers not found (404) at $0. Metadata from Crossref (crossref.org), supplied by its member publishers; bibliographic metadata is free to reuse, abstracts can carry the publisher's copyright and are left out of search results. Free, no key.