What is Postman?

Welcome back guys, first of all I would like to thank you for your kind responses for my previous post which I have explained about “How to start a blog site in 5 simple steps”, and hope you guys are well in this period of quarantine due to the attack of covid-19 virus.

This is my second blog post, it’s on “Postman Tool” and this post will explain all you should know about Postman as a beginner.

In this post, I will explain what is postman, why should we use it, and how does it work. And I think this post would be very useful for those who are interested in APIs, because Postman is an API development tool which helps to build, test and modify APIs.

First of all, I’m going to give you a brief explanation on “What is an API ?”. API stands for Application Programming Interface which is a software that works as a mediator and allows two applications to talk to each other. Each time you use an app like Facebook, send an instant message, or check the weather on your phone, you’re using an API.

As an Example, When you use an application on your mobile phone, the application connects to the Internet and sends data to a server. The server then receives that data, interprets it, performs the necessary actions and sends it back to your phone. The application then interprets that data and presents you with the information you wanted in a readable way. This is what an API is, all of this happens via API.

There are many API testing tools available on the internet such as SoapUI, Katalon Studio, Tricentis Tosca, Apigee and Rest-Assured. But I prefer Postman because it’s easy to use and it’s a free open source tool. So, let’s take a look at What is Postman.

As I mentioned before, Postman is an API development tool which helps to build, test and modify APIs. This tool includes many functionalities that required for any developer for any development process. It is used by over 5 million developers all over the world to make their API development easy and simple. It has the ability to make various types of HTTP requests such as GET, POST, PUT, DELETE, PATCH, saving environments for later use and converting the API to code for various languages like JavaScript, Python.

What are HTTP Requests ?

The internet consists vast amount of resources located on different servers. For you to access these resources, your browser needs to be able to send a request to the servers and display the resources for you. HTTP (Hypertext Transfer Protocol), is responsible for requesting and taking responses for effective communication between a client and a server. The message that is sent by a client to a server is what is known as an HTTP request.

Therefore, HTTP request methods are used to indicate the specific desired action that needs to be performed on a given resource. Each method should be implemented clearly. There are many types of HTTP request methods,

  • GET – This is used to retrieve and request data from a specified resource in a server.
  • POST – This method is used to send data to a server to create/update a resource.
  • PUT – This method is similar to POST as it is used to send data to the server to create or update a resource. The difference between the two is that PUT requests are idempotent. This means that if you call the same PUT requests multiple times, the results will always be the same.
  • DELETE – This request method is used to delete resources indicated by a specific URL.

These are the basic HTTP request methods and there are many more, but in this post, I will use this basic requests to demonstrate how does the postman work with this kind of requests that are passing through client and the server. So, lets get started !!

You can download Postman from here. And you can also download and install Postman as an extension for chrome browser, but in this tutorial i’m using Postman as a Standard Application. After downloading and installing the Postman, open the software.

After Postman is opened, this sign up window will be appeared in your screen as below. So, you have to enter valid email address and password to sign up for postman successfully.

When you have signed up successfully for Postman, you will see the startup screen as below. No need to worry about the interface, because this is very simple to use and I will simply explain how to use it step by step.

Now i’m going to demonstrate how to use this with a simple API which is created using Spring Boot and runs on embedded TomCat server. This API basically does is store IDs and Usernames that is taken from a user.

Working with GET requests

GET requests are used to get information from a given URL. There will be no changes done to the endpoint, because using this request we can only retrieve information.

I will use following URL for all the examples in this tutorial, this is very basic testing example and you can simply follow these steps.

localhost:8080/api/v1/person

In the above workspace:

1. Set your HTTP request to GET.
2. In the request URL field, input link
3. Click Send
4. You will see 200 OK Message which indicates the success of the request.
5. This section shows the data which is taken from the API
6. After you retrieve the data, your GET request is saved in history section

Working with POST requests

POST requests are used for data manipulation with the user adding data to the endpoint. Using the same URL from the previous section about GET request. let’s add our own user.

In the above workspace:

1. Set your HTTP request to POST
2. In the request URL field, input link
3. Click the body section
4. Select the JSON format to add data
5. In the body section add your data in JSON format according to your parameters
6. Click Send
7. You will see 200 OK Message
8. This section shows the posted data
9. After you create the data, your request is saved in history section

After Posting the data, you can check whether the data is successfully added to the server by following these simple steps

In the above workspace:

1. Set your HTTP request to GET
2. Click Send
3. As you can see in the picture the data has been added to the system successfully

Working with PUT Requests

PUT requests can be simply used to edit data that have been already added to the system or also used to add new data to the server from the given URL. You can follow this simple steps to make a PUT request.

In that highlighted section, I will change the name from “Will Smith” to “Jessica Jones”.

In the above workspace:

1. Set your HTTP request to PUT
2. Copy the id of “Will Smith” and paste it right after the URL
3. Change the name into “Jessica Jones”
4. Click Send
5. You will see 200 OK message

To make sure that the data has been successfully changed, send a simple GET request to the URL

Working with DELETE Request

As the name suggests DELETE Request can be simply used to delete any data in a database

I will delete “Jessica Jones” from the database to demonstrate this DELETE Request for you guys. You can follow these simple steps to delete any data from the database,

In the above workspace:

1. Set your HTTP request to DELETE
2. Copy the id of “Jessica Jones” and paste it right after the URL
3. Click Send
4. You will see 200 OK message that indicates the success of your request

Then send a simple GET request to the URL to make sure that the data has been successfully deleted from the database.

That is all and pretty simple. As you can see in this example, this is the way of how to achieve the basic GET, POST, PUT and DELETE request methods in postman to test your API.

Postman is a powerful tool for API testing. However, in order to achieve the best results and save time and effort, it must be used properly. If you are more interested about Postman you can follow this video down below.

That’s all for this post and I hope you guys enjoyed it, if you have any question about Postman or API testing just leave a comment below or contact me. I will response to your comments as soon as possible, thank you…

5 thoughts on “What is Postman?

  1. Dimanthi Liyanage

    This is so useful actually 😍❤. You are an amazing blogger. ❤ keep this work up. I’m looking forward for more interesting blogs like this in the future ❤.

    Liked by 1 person

  2. Pingback: Postman - Whiz IT Services - Information Technology Consulting & Software Development Company

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