Introduction to Postman for API Development

Postman is a powerful API development and testing tool that simplifies the process of building, testing, and managing APIs. It allows developers to send HTTP requests, analyze responses, automate workflows, and collaborate efficiently. With support for multiple authentication methods, request body formats, and automated testing, Postman has become one of the most popular tools for modern API development.

• Supports GET, POST, PUT, PATCH, and DELETE for comprehensive API interaction.
• Send data in form-data, URL-encoded, raw (JSON, XML, text), or binary formats.
• Built-in support for API keys, OAuth, Bearer Tokens, and Basic Auth.
• Organize related API requests for better collaboration and project management.
• Write test scripts in JavaScript and schedule runs for continuous integration.
• Generate and share API docs directly from requests and collections.
• Reuse and share workspaces without starting from scratch.

API Development in Postman

Postman makes it simple to send and receive requests, test APIs, and interact with servers. So, let's get started !! 

• You can download Postman from here. 
• After downloading and installing the Postman, open the software. 

Postman Interface Overview :

The Postman interface is clean and intuitive, providing all the essential tools—like request input, method selection, parameters, and response display—in a single workspace to make API testing simple and efficient.

• URL Bar: Enter the endpoint you want to test.
• Method Dropdown: Choose HTTP method (GET, POST, PUT, DELETE).
• Params Tab: Add query parameters or form data.
• Send Button: Execute the request and view the response.

This is enough to start making API calls.

Sending and Receiving Requests Through Postman

In Postman, you can send requests by selecting the HTTP method (GET, POST, etc.) and entering the API URL in the request bar. After clicking Send, Postman displays the server’s response along with headers, status codes, and data.

Sending a Get Request :

• Enter your API URL (e.g., http://localhost:3000).
• Select GET as the method.
• Click Send.
  Postman will return the response (HTML or JSON) along with headers such as content length, server type, and date.

Explanation of Headers in Postman Response :

When you send a request, Postman not only shows the main response body but also several HTTP headers that carry important information:

• Keep-Alive: Keeps the connection open for reuse instead of closing it immediately after the response. This improves efficiency.
• Content-Length: Tells the size (in bytes) of the response body (e.g., the HTML or JSON document).
• Date: Shows the exact date and time when the server processed your request.
• X-Powered-By: Indicates the technology used by the server (e.g., Express.js).
• ETag: A unique identifier for the version of the resource. If the content hasn’t changed, the server can send the cached version, saving bandwidth and time.

GET the Register Form in Postman :

To demonstrate how a GET request works in Postman, let’s fetch a register form from the server.

• Open Postman and enter the API endpoint for the register form in the URL bar (for example: http://localhost:3000/register).
• From the method dropdown (left side of the URL bar), select GET.
• Click the Send button.
• Postman will send the request and display the response in the lower panel.

Sending a Post Request :

A POST request is used to send data to the server, such as submitting a form. In Postman, choose POST, go to the Body tab, and enter the required data in form-data or raw JSON format. After clicking Send, the server responds to confirm whether the data was successfully received.

• Change the HTTP method of the next request that we are going to the send to POST. Open the Params tab of the Postman .
• This will help us in sending the form with the values that we want.

• After we hit enter, it POSTs the form with our key-value pairs and returns the response.

  

• The terminal also logs the registered user.

  

• Supports all HTTP methods, environment setup, and API-to-code conversion.
• Displays status codes, response time, and performance details.
• Allows saving, importing, and automating API tests.
• Beginners may feel overwhelmed, and APIs tested in Postman may not always work directly in browsers.
• Mostly limited to API testing and related tasks.

Create New Folder

To use Postman to test an API, start by creating a new request, naming and saving it within a collection. Set up the request by specifying the API URL, choosing the HTTP method, and adding parameters, headers, authentication, and body as needed. Organize your requests by creating folders within collections. Run the request, view the results, and optionally, write tests for automation. Save and share your work, and export collections if needed. Postman's user-friendly interface facilitates efficient API testing, providing a comprehensive tool for developers.

API Development : Creating, Sorting, and Deleting Folders with API Requests

By following below steps, you've created folders, added requests with different URLs and parameters, and demonstrated how to delete a folder. Adjust the details based on your specific needs, and make sure to execute the requests to see the responses in Postman.

Create Three Folders:

• Open Postman and click on the "Collections" tab.
• Click "New Collection" and name it "Geeks1."
• Repeat for "Geeks2" and "Geeks3."

Folder 1: Add URL to Geeks1:

• Inside "Geeks1," click "Add Request."
• Name it and set the URL to https://simple-books-api.click/.

Folder 2: Add URL to Geeks2:

• Inside "Geeks2," click "Add Request."
• Name it and set the URL to https://simple-books-api.click//books.

Folder 3: Sort Books by Type - Fiction in Geeks3:

• Inside "Geeks3," click "Add Request."
• Name it, set the URL to https://simple-books-api.click//books, and go to the "Params" tab.
• Add a parameter with key type and value fiction.

Folder 4: Sort Books by Book ID in Geeks4:

• Inside "Geeks4," click "Add Request."
• Name it, set the URL to https://simple-books-api.click//books/:bookid. Replace :bookid with an actual book ID.

Delete Folder:

• To delete a folder, right-click on the folder name in the Collections tab and select "Delete."

• By following these steps, you've created folders, added requests with different URLs and parameters, and demonstrated how to delete a folder.
• Adjust the details based on your specific needs, and make sure to execute the requests to see the responses in Postman.

Introduction to Postman

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Introduction to Postman

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