What is HTTP and what types of HTTP exist?

HTTP (Hypertext Transfer Protocol) is an application layer protocol for data transfer, mainly web pages and other resources, between a client (e.g., browser) and a server. It is based on a "request-response" architecture.

Main types of HTTP requests (methods):

• GET: Requests data from the specified resource. Used to retrieve information.
• POST: Sends data to the server to create or update a resource. Data is sent in the request body.
• PUT: Updates an existing resource on the server. Sends a new version of the resource in the request body.
• DELETE: Deletes the specified resource from the server.
• PATCH: Applies partial modifications to a resource.
• HEAD: Requests only the response headers, similar to GET, but without the response body.
• OPTIONS: Requests information about the methods supported by the server for the target resource.
• CONNECT: Establishes a tunnel to the resource identified by the URI.
• TRACE: Performs a trace of the path taken by the request to the final server.

Main types of HTTP responses (status codes):

Responses are divided into 5 classes:

• 1xx (Informational): Informational responses indicating that the request has been received and processing continues.
• 2xx (Successful): Successful responses indicating that the request was successfully processed. Examples: 200 OK, 201 Created.
• 3xx (Redirection): Redirects indicating that the client must perform additional actions to complete the request. Examples: 301 Moved Permanently, 302 Found.
• 4xx (Client Error): Client errors indicating that the request contains incorrect syntax or cannot be fulfilled. Examples: 400 Bad Request, 404 Not Found.
• 5xx (Server Error): Server errors indicating that the server encountered a problem while processing the request. Examples: 500 Internal Server Error, 503 Service Unavailable.