Ask HN: Web API platform

It occurred to me to wonder if there exists a platform for developing web API client applications? In general I'm thinking:

All the common issues handled once: OAuth, a unified data interface, workers, and a data caching layer - probably with metrics related to API rate limiting.

Ideally, single deployment (or online silo) for many apps. Users grant permissions per outside service, ideally with a minimal union of permissions required by the apps they're interested in. Apps pulled from VCS, run in a sandbox, errors reported with the request and response(s) involved.

Once I started thinking along these lines, it all seemed obvious, but the tools I've been able to find are sparse. Am I missing something?