Well, you can use the same json file for multiple documents.
By default it will be stored in the directory from which pandoc is invoked, but you can also change that by setting `url2cite-cache: filename` in the markdown frontmatter or in the pandoc invocation: `pandoc -M url2cite-cache=../bla.json --filter ...`.
By default it will be stored in the directory from which pandoc is invoked, but you can also change that by setting `url2cite-cache: filename` in the markdown frontmatter or in the pandoc invocation: `pandoc -M url2cite-cache=../bla.json --filter ...`.