Frequently Asked Questions on Using Curl to make REST API requests

Is curl secure for making API requests?

Curl itself is a tool, and its security depends on how you use it. Sending sensitive information through curl commands without proper encryption can be risky. Be cautious with API URLs containing confidential data and explore secure options like HTTPS or refer to API documentation for recommended security practices.

Can I use curl to upload files to an API?

Yes, curl supports uploading files using the -T flag. The syntax is curl -T <filename> <url>. Make sure the API endpoint you’re targeting is designed to accept file uploads.

How do I handle large API responses with curl?

For very large responses, consider using the | pipe to redirect the output to a paging tool like less or more. This allows you to view the response in manageable chunks. Alternatively, you can save the response to a file using the -o flag for later analysis.

What are some alternatives to curl for making API requests?

While curl is popular, there are other options. Tools like Postman offer a graphical user interface for crafting and testing API requests. Programming languages like Python or JavaScript also have libraries for interacting with APIs.

REST APIs are essential for modern web applications, enabling programmatic interaction with data and functionality. Curl is a command-line tool for making web requests, often used directly from the terminal. For example, curl -L ip.ba3a.tech fetches IP address details in JSON format, just like visiting the site in a browser. Essentially, Curl prints the web response to the terminal. In this article, we will learn how to make REST API requests using Curl.

For the sake of this article, let’s use a sample social media API that I have created. This will help demonstrate how to make REST API requests using cURL.

Example 1: Create (POST) Request

In this example, we use curl to send a POST request to the endpoint https://crud.ba3a.tech/users to create a new user. The -X POST flag specifies the request method, -H “Content-Type: application/json” sets the content type header, and -d ‘{“name”: “Ba3a”, “email”: “someMail@gmail.com”}’ sends the user data in JSON format.

Command:

#!/bin/bash

curl -X POST \
  -H "Content-Type: application/json" \
  -d '{"name": "Ba3a", "email": "someMail@gmail.com"}' \
  https://crud.ba3a.tech/users

Explanation:

• -X POST: Specifies the HTTP method for creating a new resource.
• -H “Content-Type: application/json”: Sets the content type header to indicate JSON data is being sent.
• -d ‘{“name”: “Ruchi”, “email”: “someMail@gmail.com”}’: Includes the user data in JSON format using the -d flag.

Output:

Example 2: Read (GET) Request

In this example, we use curl to send a GET request to the endpoint https://crud.ba3a.tech/users/1 that fetches user data based on the user-id i.e. 1.

Command:

curl https://crud.ba3a.tech/users/1

Explanation:

• curl: Command-line tool for transferring data using various network protocols. In this context, it’s used to make an HTTP GET request.
• https://crud.ba3a.tech/users/1: The URL to which the GET request is sent.

Output:

Example 3: Update (PUT) Request

In this example, we use curl to send a PUT request to the endpoint https://crud.ba3a.tech/users/3 to update the user. The -X PUT flag specifies the request method, -H “Content-Type: application/json” sets the content type header, and -d ‘{“email”: “updated.email@example.com”}’ sends the user data in JSON format.

Command:

#!/bin/bash

curl -X PUT \
  -H "Content-Type: application/json" \
  -d '{"email": "updated.email@example.com"}' \
  https://crud.ba3a.tech/users/3

Explanation:

• curl: This is the command-line tool used to transfer data with URLs.
• -X PUT: Specifies the HTTP method to use, in this case, PUT, which is used to update a resource on the server.
• -H "Content-Type: application/json": Sets the Content-Type header to application/json, indicating the data format being sent.
• -d '{"email": "updated.email@example.com"}': Specifies the data to be sent in the request body. Here, it is a JSON object updating the email field.
• https://crud.ba3a.tech/users/3: The URL endpoint for the API request.

Output:

Example 4: Delete (DELETE) Request

In this example, we use curl to send a DELETE request to the endpoint https://crud.ba3a.tech/users/3 to delete the user with ID 3. The -X DELETE flag specifies the request method.

Command:

curl -X DELETE https://crud.ba3a.tech/users/3

Explanation:

• curl: This is the command-line tool used to transfer data with URLs.
• -X DELETE: Specifies the HTTP method to use, in this case, DELETE, which is used to remove a resource on the server.
• https://crud.ba3a.tech/users/3: The URL endpoint for the API request.

Output:

Now that we know how to make REST API requests with CURL, let us see some important flags that might be useful.