This route can only be accessed by authenticated users.

The problem is that jsonapi_site.routing.yml has requirements : _user_is_logged_in: 'TRUE' , which blocks an anonymous user. I tried to remove this option and replace it with _permission: 'access content', but it did not solve the problem. Please update

Hello l1fesxff,

yes, this module does not allow to read route by anonymous users. You need to use Key Auth module to create API key and then use it in the query/header for route authentication. The reason of this is because of this module usually used on the "decoupled" Drupal sites i.e where frontend is an isolated application (written on Vue, React or some other frontend frameworks), and Drupal as the backend.