The Action Network has a full API, based on the OSDI standard. It is a HAL+JSON RESTful API, and it exposes endpoints having to deal with just about all of our functionality.
The API is useful for syncing data between systems, pulling data out of the Action Network to use for external reporting and presentation (such as creating your own map of events), posting data in from external sources or custom-built HTML forms, and building plugins and systems to take advantage of our embeddable widgets, to make embedding easier on whatever CMS you happen to be using.
It's not as useful for broad analyses, custom dashboards, or data warehousing. For that, our SQL mirror is a better choice.