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Filesvo

JSON Formatter & Validator

Paste JSON and format it with 2 spaces, 4 spaces or tabs — or minify it to a single line for production. Invalid JSON is rejected with the parser's exact error message — including the line and column whenever the browser reports a position — so you can fix it instead of hunting. Nothing is uploaded to Filesvo.

…or paste directly into the box above

Processed on your device — files are never uploaded to Filesvo.

How to use Filesvo

  1. Paste your JSON into the box, or upload a .json file.
  2. Choose the indentation — 2 spaces, 4 spaces, tabs, or Minified.
  3. Click Format JSON, then copy the result or download it.

Validation and formatting in one step

Formatting is parse-then-print: the text is parsed by the browser's native JSON engine — the same one your code uses — and re-serialized with your chosen indentation. That makes formatting and validation the same operation: if it formats, it is valid JSON, with no separate validator needed.

Because the output is re-serialized, insignificant whitespace is normalized and any duplicate keys collapse to the last value — exactly what every standard JSON parser does with duplicates. Key order and all values are preserved.

Private by design

Your files are processed directly in your browser using open-source engines that run in your browser and are not uploaded to Filesvo. Nothing is stored on our servers, because nothing ever reaches them.

Frequently asked questions

How are errors reported?
With the browser parser's own error message. When the parser reports a position, it is translated to a line and column — for example "Invalid JSON at line 3, column 18"; for some errors the browser only gives a description of the unexpected token, and that message is shown as-is.
Does minifying change my data?
No — minifying only removes whitespace between tokens. Strings, numbers and structure are untouched, and the minified form parses back to exactly the same data.
Does it support JSON with comments or trailing commas?
No — those are JSON5/JSONC extensions, not JSON. This tool validates strict JSON, which is what APIs and parsers actually accept, so a pass here means it will parse anywhere.
Is my data uploaded to a server?
No. Parsing and formatting happen entirely in your browser — your data never leaves your device.

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