The Knowledge Graph Search API is an API by Google that searches for entities in Google Knowledge Graph. The API can be used to obtain a list of notable entities that matches a certain criteria. An interesting way to the API would be to combine this with Amazon Comprehend to identify entities from a news article, etc and then to us the Knowledge Graph API to find extra information about the entity.
The Knowledge Graph supports various entities including person, companies, events, movies, books, music albums, tv series, websites, places and many more. The API uses standard schema.org types and is compliant with the JSON-LD specification.
The API can be called simply with a URL by passing the requird details as a query string. The API can be called using most programming languages. It is important to note that to call the API, an API Key needs to be obtained from Google. The key can be obtained from the Google API Console.