What is the difference between PUT and POST in REST?

PUT: Used to update or create a resource at a specific URI, replacing its current state. POST: Used to create a new resource or submit data, typically resulting in a new URI being generated.

In REST PUT and POST are two different HTTP methods used to interact with resources. PUT (Update existing resource or Create new resource): 1. Used to update or replace a resource at a specific URL or to create a new resource at a specified location if it doesn't already exist. 2. If you send the same PUT request multiple times, the result will always be the same. 3. If the resource exists at the specified URL, PUT will update it with the data sent in the request body. 4. If the resource does not exist at the specified URL, PUT can create a new resource at that location (depending on the server side logic). POST (Create new resource): 1. Used to create a new resource or to trigger a specific action. 2. If you sending the same request multiple times may result in different outcomes (e.g., multiple resources being created). 3. Typically used to create new resources on the server, where the server assigns the resource’s URL (e.g., creating a new item in a collection). Can also be used for non-creation actions like submitting a form, triggering processing, etc. Key Differences: PUT- 1. Update or create a resource at a specific URL. 2. Repeated requests give the same result. 3. The client specifies the resource URL. 4. Replace/update a resource, or create if not exists. POST- 1. Create a new resource or trigger an action. 2. Repeated requests can have different results. 3. The server determines the resource URL. 4. Create a new resource or submit data for processing. Summary: PUT is used when you know the exact URL of the resource and want to update or replace it (or create it if it doesn't exist). POST is used when you're creating a resource where the server decides the URL or when you're submitting data to trigger an action, and the outcome might vary.

In the case of REST APIs, both PUT and POST methods are used for sending data to the server. PUT is responsible for updating an existing resource or replacing it; hence, it is idempotent-the result is the same whether executed once or multiple times. POST would create a new resource and is non-idempotent; repetitions of request may result in the creation of multiple resources.

PUT: Updates a resource at a specific URI. Idempotent—sending the same request multiple times results in the same outcome.eg-PUT api/users/123 { "name": "Jane Doe", "email": "[email protected]" } here we are updating user with id =123. POST: Creates a new resource, usually without specifying the URI (the server decides). Non-idempotent—multiple requests can create multiple resources. eg-> POST api/users { "name": "Jane Doe", "email": "[email protected]" } Here we will create a new user (resource ) in server and return the status 201.