CrossRef has a lot of documentation on using our system and sometimes it can be overwhelming. This page is designed to give you some quick pointers on using our APIs to query CrossRef metadata.
First, get an API key. It takes no time at all. Just fill in the form and we will activate a key for you. Note that we do this because occasionally we need to get in touch with somebody if their scripts start misbehaving and are hammering our systems. The alternative is to simply block the script- and we wouldn’t want to do that, right?
In the following examples you need to substitute API_KEY with the key that you get from us.
OpenURL queries
Often you just want to take an existing DOI and lookup the metadata for it. For that you want to use our OpenURL query. So, if you have the DOI:
10.3998/3336451.0009.101
You can simply construct a URL like this:
http://www.crossref.org/openurl/?id=doi:10.3998/3336451.0009.101&noredirect=true&pid=API_KEY&format=unixref
And you will get an XML representation of the metadata. Unless, of course, you forgot to substitute the API_KEY in the URL above with the one that you activated in the first step... ;-)
The OpenURL query interface to CrossRef is capable of much more than just DOI lookups. You can visit our documentation to get more detailed examples of fielded searches, etc.
Free Text Queries
Sometimes you want to just search our metadata in order to enable a user to select and insert a citation or something. Be aware that we have already created a few blog plugins and a Ubiquity command to do this, but if you want to integrate the functionality into your own system, then you probably want to use our experimental “SIGG” back-end (if you have to ask- it was named after my water bottle). The following will return a JSON representation which includes metadata suitable for inserting a citation into HTML or other content. Note that, if you wanted to get the complete metadata for the entry, you could extract the DOI from the JSON and do an OpenURL query as described above.
http://crossref.org/sigg/sigg/FindWorks?version=1&access=API_KEY&format=json&op=OR&expression=allen+renear
There. That wasn’t too hard, was it?