Postman API Challenge

• Request methods

POST          Send data (Create)
GET           Retrieve data (Read)
PUT/PATCH     Update data (Update) 
              PUT usually replaces an entire
              resource, whereas PATCH usually
              is for partial updates
DELETE	      Delete data (Delete)

• Response status codes

GET :- Request Parameters

• variables :- Reuse values to keep your work DRY (Don’t Repeat Yourself) {{variableName}} -> variableName and select "Collection" as the scope, then click Set variable. example :- https://library-api.postmanlabs.com {{baseURL}}

• Query Parametes :- ? key=value -> single-> (https://website/photos?orientation=landscape) multiple ->(https://website/photos?orientation=landscape&size=500x400) example :- https://library-api.postmanlabs.com/books?genre=fiction

• path parametes :- /:id example :- {{baseURL}}/books/:id in params -> path variables -> id = 29cd820f-82f9-4b45-a7f4-0924111b5b89

POST

• add a book

body -> raw -> json { as RESTApi accepts json as body}
{
  "title": "book",
  "author": "avinash",
  "genre": "fiction",
  "yearPublished": 2025
}

• add an authorization

in headers tab -> api-key = postmanrulz
in body tab -> raw -> json
{
  "title": "postmanwa",
  "author": "avinash",
  "genre": "fiction",
  "yearPublished": 2025
}
{
    "id": "bd681e02-b583-49c8-8a1c-d53f2d8d7c1a",
    "title": "postmanwa",
    "author": "avinash",
    "genre": "fiction",
    "yearPublished": 2025,
    "checkedOut": false,
    "isPermanentCollection": false,
    "createdAt": "2025-02-27T21:26:44.314Z"
}

• Use POSTMAN Auth instead!

delete the previous api-key -> save -> go to your collection {Postman Api challenge -> authorization -> (autz type ) = api key -> add api-key = value -> save and re run POST request

• Scripting

Scripting in Postman
  Postman allows you to add automation and dynamic behaviors to your collections with scripting.
  Postman will automatically execute any provided scripts during two events in the request flow:

  pre-request script  :- Immediately before a request is sent: (Pre-request Script of Scripts tab).
  post-request script :- Immediately after a response comes back: (Post-response of Scripts tab).

scripts tab -> post-response tab ->
for example :-can access the JSON response body from an API with: 
pm.response.json()

scripts tab -> post-response tab ->
  // save the "id" value from the response to a variable named "id"
  const id = pm.response.json().id
  // save the id as a collection variable named "id"
  pm.collectionVariables.set("id", id)


fetch data only id -> create/ update the id variable
{{id}} variable is created and can be used in 'get book by id' request -> {{baseURL}}/books/:id

Patch

PATCH -> {{baseURL}}/books/:id
in params tab -> set path variable id = {{id}}   [ which book data i want to update -> checkdout = true ]
in body tab -> raw -> 
{ 
  "checkedOut": true 
}

Delete

DELETE -> {{baseURL}}/books/:id
in params tab -> set path variable id = {{id}}   [ which book data i want to delete {{id}} ]

status code :- 204 -> 404 [error not found as book is deleted 

Learning :-

Recap
Wow! You learned a ton so far. Now you know:

what APIs are
what Postman is for
how to build API requests (GET, POST, PATCH, DELETE)
how to interpret API responses
how to read API documentation
how to authorize requests to an API
how to set variables in Postman for efficiency
how to automate processes with scripts in Postman
how to generate API call code snippets for your apps using Postman's codegen feature