API

Here’s a clean study table you can add to your guide. 
 
 
 
 REST Method 
 Purpose 
 Description 
 Common Usage Example 
 
 
 
 
 GET 
 Retrieve data 
 Used to request or fetch information from a server or API. Does not modify data. 
 Retrieve customer profile, chat history, ticket status 
 
 
 POST 
 Create / Send data 
 Used to submit new data to a server or trigger actions. Often creates new resources. 
 Start chat session, create ticket, authenticate user 
 
 
 PUT 
 Update existing data 
 Used to fully update or replace an existing resource. 
 Update customer information, modify interaction settings 
 
 
 PATCH 
 Partial update 
 Used to update only specific fields of an existing resource. 
 Change customer status, update phone number only 
 
 
 DELETE 
 Remove data 
 Used to delete a resource or remove information from the system. 
 Delete session, remove user, close/delete record 
 
 
 OPTIONS 
 Discover supported methods 
 Used to determine what operations an API endpoint supports. Often used in CORS/preflight checks. 
 Browser checking allowed API methods 
 
 
 HEAD 
 Retrieve headers only 
 Similar to GET but returns headers only, without response body. Useful for validation or testing. 
 Check if resource exists, validate API availability 
 
 
 
 
 Example REST API Calls 
 GET Example 
 GET /api/customers/12345
 
 Purpose:
Retrieve customer information. 
 
 POST Example 
 POST /api/chat/start
 
 Purpose:
Create/start a new chat session. 
 
 PUT Example 
 PUT /api/customer/12345
 
 Purpose:
Update full customer record. 
 
 PATCH Example 
 PATCH /api/customer/12345
 
 Purpose:
Update only selected fields. 
 
 DELETE Example 
 DELETE /api/session/12345
 
 Purpose:
Delete session or resource. 
 
 Easy Interview Explanation 
 REST APIs 
 REST APIs allow systems to communicate using standard HTTP methods such as GET, POST, PUT, and DELETE to retrieve, create, update, or remove data.