The Compare switch adds a second textarea. Left is the original, right is jsonInputB. Still in the browser. It is not git, not a merge tool, and I didn’t paint a red/green line diff because I didn’t need one for “paste yesterday’s response next to today’s.”
Turning Compare on turns Tree View off. You can turn the tree back on and get two trees. Matching paths get highlighted when they differ, which is enough for me to spot a missing id.
Format, Minify, and Auto Fix run on both panes. Empty side is skipped. Copy dumps both texts with a blank line between them — handy and a bit crude.
Left:
{"status":"ok","count":2,"ids":[10,11]}
Right:
{"status":"ok","count":3,"ids":[10,11,12]}
Format once. count and the extra id are obvious. Trees show two vs three children under ids.
Turn Compare on, paste both sides, Format, maybe Tree View (that hides the text until you turn it off). Flip Compare off and the left document stays. For a real patch, Copy and use git.