Have you encountered systems where all operations (read, create, delete) are implemented only through POST? What are the advantages and disadvantages of this approach?

Yes, there are systems where all operations (reading, creating, deleting) are implemented via HTTP POST. This is often due to infrastructure limitations or security features.

Advantages of this approach:

• Circumvent browser or proxy restrictions: Some proxies or firewalls may block non-standard HTTP methods (PUT, DELETE), while POST is usually allowed.
• Simplify server-side implementation: All requests can be processed through a single endpoint by analyzing the request body.
• Security: POST requests are not cached by the browser and are not stored in URL history, which can be a plus for confidential data.

Disadvantages:

• Violation of REST principles: REST assumes the use of different HTTP methods for different operations, which improves API readability and standardization.
• Caching difficulties: GET requests are easily cached, POST is not, which can degrade performance.
• Idempotency issues: POST is not idempotent, complicating repeated requests without side effects.
• Debugging and integration challenges: Many tools and clients expect standard HTTP method behavior.

Overall, this approach may be justified in specific conditions, but for modern APIs, it is recommended to use standard HTTP methods according to their purpose.