The POST method requests that the server accept the entity enclosed in the request as a new subordinate of the web resource identified by the URI. The data POSTed might be, for example, an annotation for existing resources; a message for a bulletin board, newsgroup, mailing list, or comment thread; a block of data that is the result of submitting a web form to a data-handling process; or an item to add to a database.

Directions for use (REST)
The REST service interface must use the HTTP verb most suitable for the operation as indicated in RFC 7231
Message broker
the POST method is used for sending messages and creating topics / subscriptions and queues;
REST interface processing rules
POST, creating entities
Return codes and errors
POST and PATCH should never result in a 200 (generally 201, occasionally 202).