You can find the documentation here: https://world.mendix.com/display/apidocs/Deploy+API That API can be used for all your projects: not-deployed projects (only on teamserver), sandboxes-projects and projects on licenced nodes.
Edit 3 May:
Are “Personal” API keys still a thing? If so can you link me to the information on “PERSONAL” api keys? I can make an APP API key but I’m confused on existing documentation that all says there is a personal one.