Question 1

Why is my JSON invalid?

Accepted Answer

The usual suspects: a trailing comma after the last item in an object or array, single quotes instead of double quotes, keys without quotes, comments (// or /* */), NaN or Infinity, or an unescaped control character inside a string. The error message shows the line and column so you can jump straight to it. JavaScript object literals are not JSON — copy from a network response, not from source code.

Question 2

2 spaces, 4 spaces or tabs?

Accepted Answer

It is only whitespace, so the data is identical either way. Two spaces is the most common convention (npm, Prettier, most APIs); four spaces matches Python’s json.dumps(indent=4) and many editors; tabs keep files smallest while still readable. Minified output removes all whitespace and is what you should ship to production.

Question 3

Does sorting keys change the data?

Accepted Answer

No. JSON objects are unordered by definition, so sorting keys alphabetically at every level produces an equivalent document. It is useful for diffing two JSON files or for making config files easier to scan. Arrays keep their order, because array order does carry meaning.

Question 4

Is there a size limit and is the data uploaded?

Accepted Answer

Nothing is uploaded — parsing uses the browser’s native JSON.parse. Files of several megabytes format in well under a second; very large files (tens of MB) may make the browser sluggish while rendering the output box.

Question 5

How do I convert JSON to CSV or Excel?

Accepted Answer

Use the JSON to CSV or JSON to Excel converters on CalcBrew; they flatten arrays of objects into rows. This page is for validating and formatting the JSON itself.

JSON Formatter & Validator

JSON in 30 seconds

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