This validator will help you quickly (without starting up the game) check for common issues in the JSON file you select. Supports both split/unsplit Accessories, Clothes and Hair spritepack JSONs.
This is public beta. While this tool has been tested thoroughly on some official spritepack files, it could still produce false positives/negatives — if you're absolutely sure that the file is valid (or invalid), don't hesitate to test it on MAS, and consider reporting an issue.
Made by Friends of Monika ❤️