npm start starts the development server.
To obtain the json call /token endpoint.
I do no think that there is a way to obtain the data for all tokens held by an address with Web3. Token addresses must be provided in the config file. I have provided 3 of the tokens, but it will work with N number of tokens.
There is a test suite, that might be run with npm test. The test suite is not full, but I think that it shows my ability to write tests.