Among the several options that are available for authenticating with the API, the primary choice will cover one of these two options:
For a mobile, web or desktop client, that will be accessing the site externally, you will be using the OAuth method of authentication with the application of passwords or basic authentication
For themes or plugins that are running on a site, you will be making use of the cookie authentication method.
In the following sections, we will try to cover both of the options and their particulars.
The OAuth authentication method is the primary handler in authentication that is used for any external clients, making it go through the steps of a standard authentication and then authorizing the clients to act on their behalf, which are then issued with corresponding OAuth tokens that will give them access to the API that is revocable by the users at any time.
Once the WP API and the OAuth server plugins are activated on your...