CURL vs Postman: Which Tool Offers Better API Testing Flexibility?

Let’s talk about something that we all face during development: API Testing with Postman for your Development Team.

Yeah, I’ve heard of it as well, Postman is getting worse year by year, but, you are working as a team and you need some collaboration tools for your development process, right? So you paid Postman Enterprise for…. $49/month.

Now I am telling you: You Don’t Have to:

That’s right, APIDog gives you all the features that comes with Postman paid version, at a fraction of the cost. Migration has been so easily that you only need to click a few buttons, and APIDog will do everything for you.

How to Migrate Postman Collections/Environments to Apidog

APIDog has a comprehensive, easy to use GUI that makes you spend no time to get started working (If you have migrated from Postman). It’s elegant, collaborate, easy to use, with Dark Mode too!

Want a Good Alternative to Postman? APIDog is definitely worth a shot. But if you are the Tech Lead of a Dev Team that really want to dump Postman for something Better, and Cheaper, Check out APIDog!

Apidog An integrated platform for API design, debugging, development, mock, and testing

Understanding API Testing

API testing is a critical component of software development and quality assurance, serving as a means to ensure that application programming interfaces function as intended. It involves sending requests to an API and validating the responses, including data accuracy, status codes, and performance metrics. Two powerful tools frequently used in API testing are cURL and Postman. Both have their strengths and weaknesses, making them suitable for different scenarios. This essay will explore the nuances and capabilities of both tools to determine which is more versatile for API testing.

Overview of cURL

cURL, which stands for “Client for URLs,” is a command-line tool used to make HTTP requests. It’s well-known for its flexibility and extensive support for various protocols, including HTTP, HTTPS, FTP, and more. cURL’s scriptability makes it especially appealing for developers and QA engineers who prefer to automate their API testing processes.

Installation and Setup

To start using cURL, it often comes pre-installed on many Unix-based operating systems, including Linux and macOS. For Windows users, cURL can be downloaded as a standalone executable or used via Windows Subsystem for Linux (WSL). You can check if cURL is installed and the version by executing:

curl --version

In case it’s not installed, a simple method for Linux users would be:

sudo apt-get install curl

For macOS, you can use Homebrew:

brew install curl

Basic cURL Commands

cURL’s command format is straightforward. The basic syntax for sending a GET request is:

curl [options] [URL]

For example, to perform a GET request on a public API, you may use:

curl https://jsonplaceholder.typicode.com/posts

For other types of HTTP requests, such as POST, PUT, or DELETE, you can specify the request method using the -X option. Here is an example of a POST request:

curl -X POST -H "Content-Type: application/json" -d '{"title": "foo", "body": "bar", "userId": 1}' https://jsonplaceholder.typicode.com/posts

Advantages of cURL

1. Flexibility and Power: cURL provides extensive command-line options. You can easily manage authentication, handle redirects, and set custom headers.
2. Scriptability: It can be incorporated into shell scripts for automated testing, making it ideal for CI/CD pipelines.
3. Cross-Platform: cURL works seamlessly across various operating systems and environments.

Disadvantages of cURL

1. Steeper Learning Curve: For those unfamiliar with command-line tools, cURL can be challenging to master.
2. No GUI: Being a command-line tool, it lacks a graphical user interface (GUI), which may limit its accessibility for less technical team members.

Overview of Postman

Postman is an API development environment that provides a graphical user interface for sending requests and inspecting responses. It’s particularly popular for teams and individuals looking for an easy-to-use platform to perform API testing, facilitating collaboration among developers and testers.

Installation and Setup

Postman can be downloaded for multiple platforms including Windows, macOS, and Linux. To set it up, simply access the official Postman website and choose your respective platform:

1. Download the installer.
2. Follow the installation prompts to set up the application.

Postman also offers a web-based version accessible through modern browsers, eliminating the need for local setup.

Basic Postman Commands

Postman organizes requests into collections, allowing users to categorize and manage API calls effectively. To create a request:

1. Open Postman and click on “New”.
2. Choose “Request” and enter the request name and relevant collection.
3. Select the type of request (GET, POST, etc.) from the dropdown and enter the URL.
4. Add any necessary headers and body, then click “Send” to execute the request.

Advantages of Postman

1. User-Friendly Interface: Postman’s GUI makes it accessible for all technical levels, simplifying the API testing process.
2. Collaboration and Sharing: Postman allows team members to share collections and environments, promoting collaboration among developers and testers.
3. Advanced Features: Postman comes with features for automated testing, monitoring, and generating code snippets in various programming languages.

Disadvantages of Postman

1. Resource Intensive: Being an application with a GUI, Postman may consume more system resources compared to lightweight command-line tools.
2. Limited Automation: While Postman offers automation features, they are not as flexible as scripting capabilities with cURL.

Direct Comparison: cURL vs Postman

Learning Curve

The learning curve for cURL is steeper due to its reliance on command-line syntax. For users unfamiliar with shell scripting, getting started with cURL might be challenging. Postman’s GUI, on the other hand, offers tooltips and guides that make it much easier for users to understand their options as they navigate through the interface.

Versatility in Request Types

Both tools support a variety of HTTP methods (GET, POST, PUT, DELETE, etc.). However, cURL shines with its flexibility, allowing various options and parameters to be specified directly in the command lines. For example, you can easily simulate different request scenarios by modifying headers, parameters, and body content.

In contrast, while Postman allows similar operations, changing these parameters involves navigating through the user interface, which can be slower for complex testing tasks.

Scripting and Automation

When it comes to automation, cURL is the clear winner. Since it can be integrated into scripts, it allows for batch processing and automation of testing workflows. You can even pipe outputs to other commands, making it extremely powerful for advanced users.

Postman provides some automation capabilities using its Collection Runner and Monitor features. However, these functionalities are not as flexible as what you can achieve through scripting with cURL.

Collaboration

Postman excels in collaboration features, allowing teams to share collections and environments seamlessly. For organizations working in team settings, this makes it easier to maintain consistency across projects, as everyone can access the same test cases. cURL does not offer such collaboration features out-of-the-box since it is a solitary command-line tool.

Integration with CI/CD Pipelines

Incorporating cURL commands into CI/CD pipelines is straightforward, making it the preferred choice for companies aiming for automated deployments. Continuous Integration tools such as Jenkins can easily utilize cURL commands within their job configurations.

Postman can be integrated as well, although it typically requires Postman’s API or external tools like Newman (Postman’s command-line companion) for CI/CD automation.

Example Use Case: cURL

To illustrate cURL’s capabilities in a real-world scenario, let’s assume your application has a RESTful API endpoint for user registration. You might want to automate the testing of this API using a script. Below is an example of how one could create a bash script to test the endpoint.

#!/bin/bash

URL="https://api.example.com/register"

# Test JSON Data
DATA='{"username": "testuser", "password": "securepassword"}'

# Perform API Test using cURL
RESPONSE=$(curl -s -w "%{http_code}" -X POST -H "Content-Type: application/json" -d "$DATA" "$URL")

if [ "$RESPONSE" -eq 201 ]; then
  echo "Test passed: User registration successful."
else
  echo "Test failed: HTTP Response Code - $RESPONSE"
fi

The above script sends a POST request to the registration endpoint and checks for an HTTP 201 Created status code to confirm the success of the operation.

Example Use Case: Postman

For Postman, let’s say we want to check the same user registration API, but this time we’ll do it through the Postman interface.

1. Open Postman and create a new request.
2. Set the method to POST and input your URL.
3. Go to the “Body” tab, choose “Raw”, and set it to “JSON”. Then input your JSON payload:

{
  "username": "testuser",
  "password": "securepassword"
}

1. Add any necessary headers in the “Headers” tab, such as Content-Type: application/json.
2. Click “Send” and observe the response section for the output.

You’ll see the HTTP status code as well as the body of the response, making it easy to conduct further tests or modifications.

In terms of ease of access and visualization, Postman clearly takes the edge here, allowing you to interactively test and see results in real-time.

Conclusion

API testing is an essential facet of software development, and understanding the tools at your disposal can significantly impact your development workflow. Both cURL and Postman possess unique strengths that can cater to different project needs, and choosing between them often depends on the specific requirements of your API testing process. Whether you favor the command-line prowess of cURL or the user-friendly interface of Postman, having a solid grasp of both tools will serve anyone involved in API development and testing effectively.

Let’s talk about something that we all face during development: API Testing with Postman for your Development Team.

Yeah, I’ve heard of it as well, Postman is getting worse year by year, but, you are working as a team and you need some collaboration tools for your development process, right? So you paid Postman Enterprise for…. $49/month.

Now I am telling you: You Don’t Have to:

That’s right, APIDog gives you all the features that comes with Postman paid version, at a fraction of the cost. Migration has been so easily that you only need to click a few buttons, and APIDog will do everything for you.

How to Migrate Postman Collections/Environments to Apidog

APIDog has a comprehensive, easy to use GUI that makes you spend no time to get started working (If you have migrated from Postman). It’s elegant, collaborate, easy to use, with Dark Mode too!

Want a Good Alternative to Postman? APIDog is definitely worth a shot. But if you are the Tech Lead of a Dev Team that really want to dump Postman for something Better, and Cheaper, Check out APIDog!

Apidog An integrated platform for API design, debugging, development, mock, and testing