What is streaming API in Salesforce?

Streaming API enables streaming of events using push technology and provides a subscription mechanism for receiving events in near real time. The Streaming API subscription mechanism supports multiple types of events, including PushTopic events, generic events, platform events, and Change Data Capture events.

Hii Anjali,
Streaming API is your radar. It lets you define events and push notifications to your client app when the events occur. … Also, Streaming API lets you process business logic in an external system in response to data changes in Salesforce.