The practical difference
A formatter is best when JSON is already valid but hard to scan. A validator is best when you need to find syntax problems such as trailing commas, missing quotes, invalid escapes, or mismatched brackets.
When to use both
Validate first when a payload fails in an API or build pipeline. Format after validation when you need to review the object shape or share an example with a teammate.
Common mistakes
Valid JSON can still be wrong for your API. It may have missing required fields, wrong types, or values that are unsafe in your environment.
FAQ
Can a formatter fix invalid JSON?
It can sometimes point to a parse problem, but you still need to correct the syntax.
Should I validate generated JSON?
Yes. Always validate and review generated or transformed JSON before important use.