The complete REST API documentation for your system is available at https://api.us.meisterplan.com/ (for systems hosted in the US) and https://api.eu.meisterplan.com/ (for systems hosted in the EU).
You can find the hosting region at the beginning of your Meisterplan system's URL. It's the first two letters after "https://".
Want to load data into external BI tools? Create reports using the Reporting API.