I am hardly impartial, but I think Jangle makes a worthy API.

http://jangle.org/

If you're attending the Code4lib conference next week, you can learn
all about it.

-Ross.

On Thu, Feb 19, 2009 at 4:08 PM, Matthias Einbrodt
<[log in to unmask]> wrote:
> Hello,
>
> I'm interested in your opinion regarding the question which (kind of)
> APIs an OPAC should provide nowadays and in the near or maybe not so
> near future!
>
> Thanks in advance and best regards
>
> Matthias Einbrodt
>
>