IO Docs in the Wild

If you've deployed (or spotted) IO Docs out in the wild, please post the URL here, along with any information you have about the API (one sentence will do).

SendGrid API - http://iodocs.sendgrid.com - e-mail platform/API, for both sending (with high delivery rates) and programmatically processing in-bound emails.

DocuSign - http://iodocs.docusign.com - eSignature platform/API, for sending and signing documents. DocuSign's team has put a lot of custom work into their version of I/O Docs, including dynamic arrays+objects, JSON requests, and more.

GeoClique API - http://www.geoclique.me/apidocs/geoclique - a great API for location based social media.

Whit.li - http://developer.whit.li/iodocs - API to analyse social network usage