Checklist.com provides a checklist platform that helps people manage their daily lives with pre-made, interactive checklists which can be shared with anyone and accessed anywhere. The API gives users full access to the platform. With the API, users can get checklist templates or specific user checklists, tasks, contacts & settings. Applications can also make updates to this information. The API uses RESTful protocol and responses are formatted in XML.
Checklist.com is a web service for the simple task of managing checklists. It seems like a simple task, but it does it surprisingly well, including allowing access to pre-made checklists for a lot of common tasks. It recently opened its Checklist API to the public, and that API allows full access to its services for both commercial and non-commercial use.