In fact, it's a core feature of GData: https://developers.google.com/gdata/docs/json#Request
That's not to say the API will never change, but if it does, it will be documented here: https://developers.google.com/google-apps/spreadsheets/
(Disclaimer: I used to be the Google Developer Relations engineer responsible for Spreadsheets, but that was ~4 years ago.)
In fact, it's a core feature of GData: https://developers.google.com/gdata/docs/json#Request
That's not to say the API will never change, but if it does, it will be documented here: https://developers.google.com/google-apps/spreadsheets/
(Disclaimer: I used to be the Google Developer Relations engineer responsible for Spreadsheets, but that was ~4 years ago.)