First, there are three hosts
Three addresses with different jobs. This trips people up, so here it is up front.Two ways to authenticate
Which one you need depends on what you are trying to do.
Each endpoint’s
security field in the API reference tells you which one it expects.
Next steps
Quickstart
Issue an App Key and make your first API call in three steps.
Choosing an app type
Decide between an App Key app and an OAuth client app.
App Key authentication
Send your key in a header, and store and rotate it safely.
OAuth 2.0
Get user consent and call user-context APIs.
Endpoint lists, request and response schemas, rate limits, and error codes are in the API reference.