Developers use different technologies to make applications and connect different software components. To make the process easier, they look for some easy and less time-consuming ways. For example, the API development in our software can save us from writing code from scratch and save us time. But there is also debate on what cURL is.

cURL command line interface is also preferred these days. It can help transfer data from and to the server. However, some complications make it hard to differentiate between an API development and a cURL. Although both are different concepts, people get confused about them.

What Is cURL?

Why Should We Use cURL?

What Is The Difference Between A cURL and an API?


How Does cURL Relate To APIs?


HTTP Method



How To Use cURL?


What Is cURL, And How Does It Vary From An API?

What Is cURL?

cURL stands for client URL, which helps developers transfer data to and from the server.

In simple words, cURL specifies the location to help us talk to the server. It also specifies the data that we want to send.

The best part about cURL is that it supports almost every protocol. Moreover, we can use it easily on any platform of our choice.

cURL is considered an ideal way to perform communication testing from a local server to most edge devices.

Below is an example of a basic command in cURL: 

In a cURL command, we can see that a URL follows it. It would help us retrieve some kind of data.

In the command above, we would get an HTML source for

To define cURL in simple words, we can say that it is just a command line tool. It uses the libcurl library to perform its functions without user interaction.

What Is cURL, And How Does It Vary From An API?

Why Should We Use cURL?

There are so many reasons to use it for multiple projects. Some main reasons are listed below:

  • Highly portable
  • Compatible with almost every operating system
  • Useful to check if the endpoints are working or not
  • Helpful for debugging
  • Good error logging
  • Rate limited

What Is The Difference Between A cURL and an API?

The difference between the two is quite clear. cURL is just a command line tool that helps transfer data.

On the other hand, API is a software interface. To make everything clear, let’s move to the detailed description. We have already cleared the idea of cURL in the above sections.

Now let’s move to what an API can do for us.


An API stands for an application programming interface. It can help two or more computers communicate with each other.

In simple words, we can say that it provides services to another piece of software. It communicates with a set of protocols or definitions for two software components.

Read: What Is An API Key?

It is also important to know an API key when working with an API. It is a unique identifier to authenticate a calling program to an API.

Let’s take an example of weather data. We have a feature in our phones that gives us detailed weather data.

It happens because our phone talks to the weather bureau’s software system using APIs. The APIs make it possible to give us weather data.

We can say that APIs act as a bridge between two software components.

APIs consist of the three main protocols listed below:

  • RPC
  • SOAP
  • REST

It is important to know about SOAP vs REST before implementing them.

How Does cURL Relate To APIs?

These terms are also related to each other. It’s because we can send API requests using cURL. We can see that each API request is generally composed of four main parts.


An endpoint acts as an address or URL that helps send the API requests.

HTTP Method

HTTP methods used for sending API requests are enlisted below:


It can help us delete a resource, such as a database entry.


It can help us update or create a resource, a file, or a record in a database.


We can send the necessary information to the server using the POST method.


It can help us retrieve a resource from our server.

When implementing the HTTP methods, the methods mentioned above are always recommended. However, it depends on the implementation and specification of API to use particular methods.


Headers contain detailed data, such as metadata about the API request. It may contain user agents, content types, and so on.


The body consists of the whole message that we want to send. In most cases, we can use PUT and POST methods in the body.

How To Use cURL?

cURL uses Libcurl, a free URL transfer library working on the client’s side. It is most commonly used for connection troubleshooting and data transfer. Let’s learn how to use it.

  • First of all, we need to check the version installed by the following command:

curl –version

  • When we run this command, it will show the version and a list of supported protocols. Now, let’s begin with using cURL through the help of some examples.
  • The basic command looks like this:

curl [OPTIONS] [URL] 

  • It will help us show the contents of a page.
  • If we have a test domain, we can use the following code to show the home web page:


  • It will help us render our home page’s full source code. If we don’t specify any protocol, cURL will make it HTTP.What Is cURL, And How Does It Vary From An API?
  • cURL command can also help us download several files through a remote location.
  • -O will help you save the file in your current directory, which will be saved with the same name. For example:

curl -O 

  • -o will help you save the file with a customized name. For example:

curl -o newtestfile.tar.gz 

  • If the download process is interrupted, we can resume it using the following command:

curl -C – -O 

  • We can list all these in a file if we want to download several files using different URLs.
  • We can combine commands with xargs for downloading different URLs.
  • Now suppose that we have a file allUrls.txt, and this file consists of all the files we need to download. We can use the example given below to download all the files:

    xargs –n 1 curl -O < allUrls.txt


What is cURL used for?

A cURL is used for transferring data from and to the server.

Why is it called cURL?

It stands for client URL that helps developers in data exchange.

What is meant by cURL software?

It is software that encompasses libcurl development library and a command line tool.

Is cURL a coding language?

It is a reflective, object-oriented programming language we can use for interactive web applications.


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