What are the differences between the basic HTTP methods GET, POST, PUT, PATCH, DELETE?

HTTP methods define the type of operation the client wants to perform on the server:

• GET — requests data from the server. Does not change the state, is idempotent and safe. Used for retrieving information.
• POST — sends data to the server to create a new resource or perform an operation. Not idempotent, may change the state.
• PUT — replaces an existing resource or creates it if it does not exist. Idempotent, meaning repeated requests with the same data give the same result.
• PATCH — partially updates a resource, changing only specified fields. Not necessarily idempotent, depends on implementation.
• DELETE — deletes a resource. Idempotent, repeated deletion of the same resource does not change the result.

Example in C# using HttpClient:

var client = new HttpClient();

// GET
var response = await client.GetAsync("https://api.example.com/items/1");

// POST
var content = new StringContent(jsonData, Encoding.UTF8, "application/json");
response = await client.PostAsync("https://api.example.com/items", content);

// PUT
response = await client.PutAsync("https://api.example.com/items/1", content);

// PATCH (using HttpMethod)
var method = new HttpMethod("PATCH");
var request = new HttpRequestMessage(method, "https://api.example.com/items/1") { Content = content };
response = await client.SendAsync(request);

// DELETE
response = await client.DeleteAsync("https://api.example.com/items/1");