When a web browser sends get requests to an API, the API sends back only data, the developer then is free to use all the data! For example, The City of Chicago has a webpage that stores all of their data, and by law, these data are all open to public to use! I used a Historical Landmark API and got a list of all the historical landmarks in Chicago and I created an app that displays all of the entry in a readable way! (not in array of hashes)
Trello keeps track of everything, from the big picture to the minute details. For free! https://trello.com/
MockFlow is an online wireframe tool for software and websites. https://mockflow.com/
SQL Designer http://ondras.zarovi.cz/sql/demo/