Open /dev/json-format and paste the text. Format expands with indentation; minify strips whitespace.
If parse fails, jump to the reported position: missing commas, trailing commas, and single quotes are the usual causes.
Use JSON field search to extract a few keys, and JSON validate when you only need a yes/no plus an error hint.
Do not paste secrets into random third-party formatters. This tool stays in the browser; still clear production keys from the tab when you are done.