Please refer to the Setting up the Rest Client section of Chapter 3,  Cloud Vision API, to set up a REST API client, either Postman or cURL, before you continue. Now that we have all the required setup done, let's get started with exploring the API. In this section, we are going to explore two APIs of the Cloud Natural Language API:

• Sentiment analysis
• Entity analysis

There are three more APIs that are offered as part of the Cloud Natural Language API, which are as follows:

• Syntax analysis
• Entity sentiment analysis
• Classifying content

While integrating with SmartExchange, we are going to make a request including all five features. But while working with Postman, we will be working with only two of them. We will start with sentiment analysis.