  Nowadays, invoking third party code increasingly involves calling web
services via their web APIs, as opposed to the more traditional scenario of
downloading a library and invoking the library's API. However, there are also
new challenges for developers calling these web APIs. In this paper, we
highlight a broad set of these challenges and argue for resulting opportunities
for software engineering research to support developers in consuming web APIs.
We outline two specific research threads in this context: (1) web API
specification curation, which enables us to know the signatures of web APIs,
and (2) static analysis that is capable of extracting URLs, HTTP methods etc.
of web API calls. Furthermore, we present new work on how we combine (1) and
(2) to provide IDE support for application developers consuming web APIs. As
web APIs are used broadly, research in supporting the consumption of web APIs
offers exciting opportunities.
