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Kumar Kalyan
Kumar Kalyan

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Postman API 101 (Learn the basics of API using Postman)

What is an API and how does it work?

Application Programming Interface or API is a pipeline to transfer data from client application to server and vice versa in from of requests and responses or in other words an API acts as a medium of communication between the client and server over a network. Imagine that you went to your favorite restaurant, sitting on the table you call the waiter to order something (say pizza) then the waiter pass your order to the chef. Now there are two possibilities either you get your pizza or the waiter returns with a message that "Sorry sir the pizza you just ordered is currently out of stock please order something else "

Here you are the client-side application the chef is the server and the waiter is an API who is passing your request to the server and brings a response for you.

restaurant

Why do we need an API?

Consider a situation where you are building an app like Uber and it will have some basic services like authentication, maps for location service email service for sending invoices and newsletters or a payment service for accepting payments. Now you can access all these services through API's like Google maps for location services auth0 for handing the authentication amazon sqs for emails and stripe for payments. All I want to say is that you can access any software service throughAPI's who don't have to create all these services from scratch. Also using an API will be more cost effective than creating a service from scratch. And believe me there is an API for everything, all you need to do is implement.

API

What is Postman and why should we use it?

Postman is an API collaborative development tool which makes it easy to create, test, develop and use an API through a wonderful UI. And it is used by global and top fortune organizations like PayPal, Uber , etc. So test any API , you can share your works or develop an API with you team at the same time using a public or private workplace. You can even write tests or check for security issues, and many more.

using postman

Request and Response in depth

As I have mentioned earlier, how an API works now let's understand about the request and responses in depth. Talking about request when you search for something in google you are actually making a request to the google server passing a query. See the image below, you can see the url is https://www.google.com/search?q=hello here https:\\ is the protocol for your request www.google.com is the address of the server , \search is the endpoint and ?q=hello your query.

google search

Don't get confused, I am making it easy for you. Suppose the teacher asked Ram to bring him a book for the library. HereAsking is the request protocol ram is the host name for the server, library is the endpoint and book is the query

client.png

Request methods

method.png

Now if you have requested something you are definitely going to get a response with a status code.
Making it simple, your search results will be your response. An API can return a repose in many forms like Html, XML, JSON ,etc. and the most important thing that a response brings is a status code. Status codes helps us to understand the type of our response. Suppose if you send a GET request you may get data with a satus code of 200 means success or may get 404 means not found or if you send PUT or POST or DELETE you may get 201 for created 204 no content or 500 internal server error .

Start using postman

Create a postman account

Create a workspace (means creating a project)

Go to Home>Workspaces>Create Workspace
create workspace

Name your workspace> Add a summary > select the visibility > hit on Create Workspace

create workspace 2

Create a collection

Collection means group of saved requests. We can create a new collection or can simply fork (means copying) a collection to our workspace. To create a new collection in your workspace, in the left click on+ > add a name to your collection > click on : to add a new request

create collection

add name

add request

Fork a collection

visit a collection > click on ... > scroll down and select create a fork> add a label and select your workspace location > click on create fork

fork1

fork 2

fork created

get

A getrequest is used when we want to get some data from an API.
Suppose If I ask you that what is name?
you will reply me your name (Say, my name is Jhon).
In this example you are the API, my question is the get request and your answer is the response. Now let's perform this task in real.

Open the postman click on the + tab to create a new request and then select Get request form the dropdown and paste
this URL in the Enter request URL place holder and then click on the send


So, in this above video you can see that on sending a get request using postman, we got a response i.e. data as JSON (JavaScript Object Notation) with a status code 200.

post

A post request is used when we want to send data to a server using an API.
Suppose you have written something on a paper, so in this case what you have written is the data and the pencil you are using is the API and the paper is the server.

Now again in the postman then paste the same URL, this time choose post request from the dropdown, then click on body > raw >json and write some json content in the placeholder and hit the send button

{
"userId": 697,
"id": 10,
"title": "post request ",
"body": "this request is created by kk"
}

put

A put request is used when we want to update any data that we have posted earlier to the server, using API.
Suppose you have written an essay on a paper and now you want to update something in it, in this case Your pencil will be API and the paper will be the server and you can update anything on the paper

Now again in the postman then paste the URL, this time choose put request from the dropdown, then click on body > raw >jsonand write some json content in the placeholder this time lets change the content

{
   "title":"This title is updated" 
}
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We have again got a status 200 which means that output request was successful

delete

A delete request is used to delete some data from a server using an API.
Considering the last example, after writing an essay, now you want to erase it using an eraser, in this case your paper will be the server and eraser will be the API.
Now again in the postman let's send a delete request to this URL,


We have again got a status 200 which means that output request was successful

Conclusion

I hope this article will help everyone to acquire adequate knowledge required for getting started with postman. Feel free to share this article with your peers and do hit a ❤️ if you love my article. Feel free to ask any query in the comment section.

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