How to use APIs in your Joomla website

How to use external data in your Joomla 4 website? Or how to make available data via your Joomla 4 website to external websites or programs?

An Application Programming Interface is a connection between computers, programs or websites.
How can you make use of external APIs in your Joomla website?

New in Joomla 4 is the core Webservices API that you can use to connect your site from external websites/applications.
How can you use the Joomla 4 core Webservices API?

Peter talks about APIs and discusses some use cases. He shows how you could make use of external APIs and of the Joomla 4 Webservices API.