There is IMPORTXML function to import data from any of various structured data types including XML, HTML, CSV, TSV, and RSS and ATOM XML feeds.
Is there any similar solution to import data in JSON format?
Currently there is no any Add-on which offer this functionality, so you have to create or import custom functions by Script Editor available in Tools menu (for Spreadsheet). Then re-paste the content of
ImportJSON.gs from bradjasper's GitHub page and save it.
After that, you can use
ImportJSON function, for example:
=ImportJSON("http://gdata.youtube.com/feeds/api/standardfeeds/most_popular?v=2&alt=json", "/feed/entry/title,/feed/entry/content", "noInherit,noTruncate,rawHeaders")
Here is another example: