Simple definition
The HTTP POST method submits data to a server for processing or resource creation.
Purpose and use
POST asks a resource to process submitted data, for example to handle a form or create an item.
How does it work?
Behavior depends on the endpoint; POST is not inherently idempotent, so repeating a request can produce multiple operations.
Example and verification
For duplicate-sensitive creation, test behavior after a network interruption and the API's identification or deduplication mechanisms.
Points to watch
POST does not encrypt data; HTTPS protects transport. Cookie-based sessions may also require suitable CSRF protection.
In short
The method requests processing; duplicate prevention and access guarantees must be designed into the service.