What is feeditem in Salesforce?
FeedItem represents an entry in the feed, such as changes in a record feed, including text posts, link posts, and content posts. This object is available in API version 21.0 and later. This object replaces FeedPost. FeedItem | Object Reference for Salesforce and Lightning Platform | Salesforce Developers
What is a custom object feed in Salesforce?
A custom object feed shows posts and changes to the object’s tracked fields. The object name is variable and uses Custom Object__Feed syntax, where Custom Object is the name of the custom object. For example, Textile__Feed represents a feed on the custom object Textile__c.
How do I create a custom feed?
A feed for a custom object is automatically created when a user enables feed tracking for the custom object. Use feeds to track changes to the custom objects they serve. For example, Textile__Feed tracks changes to a Textile__c object. Use feed objects to retrieve the content of feed fields, such as type of feed or feed ID.
What version of Salesforce is the feedpost object available in?
This object is available in API version 21.0 and later. This object replaces FeedPost. FeedItem | Object Reference for Salesforce and Lightning Platform | Salesforce Developers Share your feedbackabout our new site.

Example: Parsing a JSON Response from a Web Service Callout
This example parses a JSON-formatted response using JSONParser methods. It makes a callout to a web service that returns a response in JSON format. Next, the response is parsed to get all the totalPrice field values and compute the grand total price.
Example: Parse a JSON String and Deserialize It into Objects
This example uses a hardcoded JSON string, which is the same JSON string returned by the callout in the previous example. In this example, the entire string is parsed into Invoice objects using the readValueAs method.
