JSON Viewer & Validator
Paste JSON below to check it, pretty-print it, minify it, or explore it as a collapsible tree. Everything runs in your browser.
How to use the JSON viewer
Paste your JSON into the box and choose an action. Format adds indentation so nested objects are easy to read. Minify removes all whitespace to make the data smaller for APIs and config files. Validate checks the syntax and tells you the line and column of the first error. Tree view shows the structure as expandable sections, which helps with large responses.
What makes JSON invalid?
JSON is strict. The most common mistakes are trailing commas after the last item, single quotes instead
of double quotes around strings, unquoted keys, comments (JSON does not allow them), and values such as
undefined or NaN. The validator points you to the exact spot.
Is my data safe?
Yes. The formatting, validation and tree view run in your browser. The text you paste is not sent to any server, and nothing is stored between visits.
Frequently asked questions
Is the JSON viewer free?
Yes. There is no sign-up and no limit on how often you use it.
Can it handle large files?
It works well for responses up to a few megabytes. Very large files can be slow to render in the tree view, so use Format or Minify for those.
What is the difference between formatting and validating?
Validating only checks whether the JSON is correct. Formatting checks it too, then rewrites it with consistent indentation. If the input is invalid, neither can produce output.