Related to the use of the MediaWiki API on Wikipedia. Consider also the tags [wikipedia] if your question isn't about the API or [mediawiki-api] if your question isn't about Wikipedia.
Documentation for the API is available at mediawiki.org; a summary of all available parameters and short help is available by accessing the API endpoint on the wiki.
In addition, there is a REST API that allows fetching commonly used data in a simple format. A list of all endpoints can be found in the REST API Documentation.
Please make sure to read the etiquette for best practices for using the API and general usage guidelines.
