bch-api is a REST API, allowing modern applications to interact with the BCHA blockchain. New to the BCHA blockchain? Check out these bitcoinabc.org.
While you'll be able to run through the examples without one, you should sign-up for a free API key in order to unlock higher rate limits.
This web server is based on rest.bitcoin.com. Most endpoints are common between the two projects. You may want to plan with their interactive UI to explore the API endpoints.