I (and others [edit just want to emphasise that I was part of a team, reading this back later sounded like I was saying a few people chipped in rather than a whole team all worked on it full time]) built GRID: https://grid.ac
So if you count that as an API, we offer it because the whole project is about getting people to use persistent identifiers for research institutes and using that in their workflows. Free an public data is required for this to work well, and making it easier to hook into your processing is vital.
Selfishly, if people used persistent IDs more then my job and the work my company does would be significantly easier, so giving people a free way of doing this and making it as easy as possible for them helps move the field I'm in forwards. Also, when we have grid ids in our data outputs, we want people to be able to use them & get extra metadata. Making our own products easier to use & integrate adds value as well.
Each page is machine readable: https://grid.ac/institutes/grid.5335.0 -> https://grid.ac/institutes/grid.5335.0.json (other formats work too, like nt for triples, and accept headers can be used instead but I can't make those into a link).
So if you count that as an API, we offer it because the whole project is about getting people to use persistent identifiers for research institutes and using that in their workflows. Free an public data is required for this to work well, and making it easier to hook into your processing is vital.
Selfishly, if people used persistent IDs more then my job and the work my company does would be significantly easier, so giving people a free way of doing this and making it as easy as possible for them helps move the field I'm in forwards. Also, when we have grid ids in our data outputs, we want people to be able to use them & get extra metadata. Making our own products easier to use & integrate adds value as well.
Edit - you can see others using the ids here:
http://www.bookmetrix.com/detail/book/2062f9b3-4e4f-4f00-b79... under affiliations
They're in the Altmetric top 100 lists https://www.altmetric.com/top100/2016
Linked up in scigraph: https://github.com/springernature/scigraph/wiki
It's used in wizdom.ai's visualisations https://wizdom.ai/public/analysis/brexit/dashboard?chromeles...
They pop up elsewhere too, but those I knew I had the links to handy.