Paste a minified API response and read it. Format with 2 or 4 spaces, validate the syntax and see the position of the first error, minify before shipping, and sort every key for a clean diff. The parsing happens in your browser, so the payload never leaves the tab.
Format, validate, minify and sort, plus indent control, counters and a copy button in the same panel.
A single line of minified JSON becomes an indented tree you can scan in seconds.
The parser message names the problem, and the line is shown where the browser reports a position.