How to pass parameters from the response of one request to another request in API auto-testing in Postman?

1. Getting the value from the first response:

   In the "Tests" section of the first request:

   // Parse JSON response
   const responseJson = pm.response.json();
   
   // Get the value of the required field (e.g., id)
   const itemId = responseJson.id;
   
   // Set an environment variable or a global variable
   pm.environment.set("itemId", itemId);
   // Or for a global variable: pm.globals.set("itemId", itemId);
   

2. Using the parameter in the second request:

   In the second request, in the URL, body, or headers, use the syntax {{variableName}}:

   For example, in the URL:

   GET /api/items/{{itemId}}

   When running the collection or sequence of requests, Postman will automatically substitute the value of the "itemId" variable set in the first request.

Additionally: You can use the "Pre-request Script" tab in the second request for more complex logic before it executes, if necessary. For example:

// Get the value of the environment variable
const itemId = pm.environment.get("itemId");

// Or get the value of the global variable: const itemId = pm.globals.get("itemId");

// Perform some actions with the obtained value before sending the request
// For example, log it
console.log("Using item ID:", itemId);