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Make unreadable JSON readable
An API response usually arrives on one line with no spacing — efficient for a machine, unreadable for a person. This tool indents the data so its structure becomes visible and you can see at a glance which field sits inside which object.
It works the other way too: minify readable JSON back down to a single line to drop the whitespace. Useful for trimming configuration files and request bodies.
It tells you where the error is
The maddening thing about JSON is that one missing comma invalidates the entire document, and error messages often will not say where. This tool validates the data and reports where the problem is, so you are not scanning the whole file by eye.
Three mistakes account for most failures: a trailing comma after the last element, single quotes instead of double quotes, and unquoted key names. The JSON standard permits none of them.
Your data never leaves your browser. That matters when you are inspecting a response from production: pasting a body containing customer data or an access key into an unfamiliar website is disclosing it.
How to format and validate JSON data
Step 1: Paste your JSON
Drop in your API response or the contents of a configuration file.
Step 2: Format or minify
Format it to make it readable, or minify it to a single line to shrink the file.
Step 3: Fix any errors
If the data is invalid, the tool reports where the problem is. The usual culprits are trailing commas, single quotes and unquoted keys.
Step 4: Copy the result
Copy the corrected, formatted output into your code or documentation.
Frequently Asked Questions
Is my data sent to a server?
No. Parsing and formatting happen entirely in your browser. That distinction matters when the payload you are inspecting contains sensitive data.
What does “unexpected token” mean?
The parser hit a character it was not expecting at that position. In practice it is nearly always one of three things: a comma left after the final element, single quotes instead of double quotes, or a key name that is not in quotes.
Can I use comments in JSON?
Standard JSON has no comments; adding `//` or `/ /` makes the document invalid. Some tools accept a relaxed variant, but those files will not parse in standard parsers.
Can it handle very large files?
A few megabytes is fine. Much larger files can strain the browser tab, because all the work happens on your device.
Does minifying change my data?
No. Only insignificant whitespace such as indentation and line breaks is removed; the data itself is identical.
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