The Insightly Ruby SDK by Insightly allows to access the API to integrate customer relationship management features. Sample code presents how to interact with contacts and handle errors. Documentation available at https://api.insight.ly/v2.1/Help
Our API directory now includes 63 CRM APIs. The newest is the PingGiant API. The most popular, in terms of mashups, is the Salesforce API. We list 44 Salesforce mashups. Below you'll find some more stats from the directory, including the entire list of CRM APIs.
The Ontimenow Scrum API is an Agile management tool with REST calls and JSON responses, and uses Oauth2 authentication. The API allows calls to check contacts, view defects, check features, tasks, incidents, projects, releases and users.