ipuz is a file format popular across the Internet. It describes multiple puzzle formats, including crosswords, sudoku and acrostics.
ipuz is a trademark of Puzzazz, Inc.
ipuz is used as the submission format for crosswords for The Age and Sydney Morning Herald daily newspapers in Australia.
The Puzzazz application apparently has an interface to New York Times crosswords for NYT subscribers, so ipuz may also be used there.
The commerical crossword setting software Crossword Compiler lists ipuz among its supported formats.
The canonical location of the format is ipuz.org. I have been trying to connect to this site for a couple of days and getting active disconnects.
The DNS A record for ipuz.org:
ipuz.org. 3600 IN A 162.255.119.254
Ipuz files are formatted in JSON.
The most informative site is the justsolve archive which states:
ipuz is intended as an openly-documented format for data files of puzzles such as crosswords and sudoku. In contrast to "proprietary" formats such as PUZ, there is an official spec available freely and released under a Creative Commons license (BY-ND 3.0), instead of the format having to be discovered by reverse engineering subject to possible hassles by intellectual-property owners. It was created and released by the puzzle technology company Puzzazz, which was the first company to use it.
We have two ipuz samples in the data directory, here and there. The links are to YAML conversions of the original JSON-formatted code - for ease of human reading!
There is a Python library, ipuz, for reading and writing puzzles in ipuz format. It holds more information about the structure and versions (v1 and v2) of ipuz.
After a quick inspection, the ipuz format has some similarities to the puz format.
The Python library could serve as a basis for a JavaScript converter if we wish to load ipuz files directly from the browser UI.