cURL Post Request

Explore using cURL for POST requests in our tutorial. Get detailed steps for sending POST requests from the command line effectively.

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Tuan Nguyen
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In this article, we’ll show you how to make POST requests using cURL. cURL is useful data over the internet. It supports different ways of communicating online, including websites (HTTP, HTTPS) and file transfers (FTP). POST requests are a way to send data to websites, and with cURL, doing this is as simple as typing a single line of text on your computer’s command prompt

Making POST Requests

Start by installing cURL if it’s not already on your computer. Here is a table below that will help you understand cURL better. For example, the process of making a POST request can be simplified as follows:curl -X POST -d "Hello"

Here, the -X flag specifies the HTTP method, while the -d flag includes the data sent to the server. This foundational knowledge in data transfer is complemented by understanding market trends and data analysis, where tools like the Google Trends API come into play, providing insights into the popularity and usage of programming languages and technologies.

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This table showcases the essential cURL command-line options you’ll be working with in the upcoming sections. There’s no need to commit them to memory immediately, just skim through them for now. As you begin to use cURL regularly, these commands will naturally become nature to you. Plus, you can always refer back to the complete list of cURL options, including those mentioned, by utilizing the --help option:

curl --help

The fundamental structure for making a POST request with cURL is outlined as follows:

curl -X POST -d "Hello"

Take note that the -X flag, followed by POST, signals to cURL to use the POST method, a way websites receive data, according to the rules of the HTTP protocol. The -d flag is used to include the message “hello” that you send to the websites at The -X flag is just a shorter way to say --request. To get to know the longer forms of these and other command options, you can look at the table we mentioned earlier.

Setting the Content-Type

Just like other HTTP requests, POST requests made with cURL can include custom headers. To define the Content-Type header, it must be established using the header flag.

curl -X POST -H "Content-Type: text/plain" -d "Hello"

In this command, we introduce an extra -H flag that allows users to configure the request headers. Here, by setting the Content-Type header to text/plain, you inform the web server that the data being sent in the request body is in TEXT format.

Sending JSON Data

You can also transmit JSON data within the request body. This requires setting the correct Content-Type header and using the -d flag to include the JSON data. cURL then carries out a POST request using the JSON data provided as an argument.

curl -X POST -H "Content-Type: application/json" -d '{"key":"value"}'

For tasks that require handling large amounts of data or complex data structures, leveraging the Google SERP API can simplify the process of data retrieval and analysis, making it an invaluable resource for developers working with web technologies.

Posting XML Data

Just as with JSON, it’s feasible to dispatch XML within the request body. This involves modifying the request header to indicate the Content-Type as application/xml.

curl -X POST -H "Content-Type: application/xml" -d '<?xml version="1.0" encoding="UTF-8"?><root><name>John Doe</name><age>30</age></root>'

As you can see, the command shown is used for uploading an image file. Immediately following the -F, the file path of the image is specified. To upload several files to the server, you can employ -F flags as shown in the example below:

curl -X POST -F "file=@/path/to/img1.png" -F "file=@/path/to/img2.png"

Sending Authentication Details

The -u flag or the --user option allows you to input the username and password required for basic authentication. cURL then constructs the Authorization header using the information you provide.

curl -u username:password


cURL simplifies the process of making POST requests, allowing for the transmission of data in various formats. It's an indispensable tool for developers, offering flexibility and power without a graphical interface. While cURL excels in its domain, it's also essential to leverage other resources and tools for comprehensive data analysis and web scraping tasks, such as the Google SERP API, which offers advanced capabilities for extracting search engine data.


Q1. What does a cURL POST mean?
A1. A cURL POST describes the action of executing a POST request through cURL. cURL serves as a flexible and commonly used command-line interface (CLI) tool for executing HTTP requests. Using a POST request via cURL involves dispatching data to a server or API, with this data to a server or API, with this data generally being part of the request’s body. Using the-X POST command alongside the relevant data and URL allows for the initiation of a POST request.

Q2. Is it okay to use cURL instead of Postman?
A2. Yes. cUrl possesses the required capabilities for using HTTP requests. If you are comfortable with the Command Line Interface (CLI) and prefer using command line tools, you will find cURL’s CLI to be extremely beneficial. Nevertheless, cURL lacks a graphical user interface (GUI) similar to Postman. Moreover, several of Postman’s sophisticated features, including request history, automated testing, and team collaboration tools, are absent in cURL.

Q3. What are my other options besides cURL POST?
A3. Postman and Insomnia stand out as favored choices among developers seeking alternatives to cURL for making POST requests. Additionally, programming languages like Python, Ruby, Go, among others, offer HTTP libraries capable of handling both GET and POST requests, providing versatile options for developers.

Q4. What sets POST apart from GET in cURL?
A4. In cURL, GET and POST methods are used for different tasks, mainly differing in their approach to data transmission to a server or API. GET communicates data using URL parameters and queries to fetch information, whereas POST transmits data via the request body, hiding the data from being visible in the URL. Therefore, POST is viewed as more secure than GET, often being the preferred method for sending confidential information.