cURL & HTTP Terms in Java

Make HTTP requests from the terminal using cURL, understand HTTP methods, headers, request/response structure, and query parameters.

What is cURL

cURL is a command-line tool used to send HTTP requests directly from the terminal and inspect responses.

1. Definition of cURL

What cURL actually is.

2. Why Backend Developers Use cURL

Practical backend usage.

Using cURL

cURL can simulate almost any HTTP client behavior.

1. GET Requests

Fetching data.

2. POST Requests

Sending request body.

3. Debugging with cURL

Inspecting raw HTTP.

Form Data with cURL

Apart from JSON, APIs and servers often receive data as form data, especially from HTML forms and file uploads.

1. Sending Form Data

Using cURL to send form-encoded and multipart data.

HTTP Overview

HTTP (HyperText Transfer Protocol) is the foundation of communication between clients and servers.

1. Request–Response Model

How HTTP communication works.

2. Stateless Nature of HTTP

Why HTTP does not remember clients.

HTTP Methods

HTTP methods define the intent of a request.

1. Read & Safe Methods

Methods that do not modify data.

2. Write & Modify Methods

Methods that change server state.

HTTP Headers

Headers carry metadata about requests and responses.

1. Request Headers

Headers sent by clients.

2. Response Headers

Headers sent by servers.

Status Code & Status Message

Every HTTP response includes a numeric status code and a textual status message.

1. Status Code

Numeric response indicator.

2. Status Message

Human-readable description.

HTTP Body

The body carries the actual data being sent.

1. Request Body

Data sent by client.

2. Response Body

Data returned by server.

Cookies & State

Although HTTP is stateless, cookies allow servers to maintain state.

1. What Are Cookies

Client-side storage.

2. Cookies vs Headers

Where cookies fit in HTTP.