🧩 JSON Formatter & Validator
Beautify your JSON with custom indentation, minify it to one line, and validate it with line/column error reporting. Everything runs in your browser — your data never leaves this page.
Your result will appear here.
What is a JSON Formatter & Validator?
A JSON formatter turns messy or single-line JSON into a readable, indented format, while also checking whether the data is valid. It is ideal for quickly beautifying (pretty printing), minifying and validating JSON when you are inspecting API responses, editing config files or debugging data from a webhook. In this tool every operation happens in your browser; the data you paste is never sent to a server, so you can safely process sensitive API keys and private payloads.
How to use it
- Type or paste raw JSON into the box above. Use the Load Sample button to try it instantly.
- Choose 2 spaces, 4 spaces or tab as the indentation.
- Use Beautify for indented output, or Minify for a single-line compact result.
- Validate only checks validity; on failure it shows the message and the approximate line/column of the error.
- Use Copy Output to send the result to your clipboard.
Worked example
Suppose an API returns {"name":"Ada","roles":["admin","editor"],"active":true}. Paste it and press Beautify: the tool first parses the data with JSON.parse, then re-serializes it with your chosen indentation. Keys are stacked vertically, arrays become readable, and the status bar shows "Valid JSON" along with the root object/array item count and the size in bytes.
Common JSON mistakes
- Trailing comma: a comma after the last element (e.g.
[1, 2, 3,]) is invalid in JSON. - Single quotes: JSON only accepts double quotes — use
"text"instead of'text'. - Unquoted keys: every object key must be wrapped in double quotes.
- Extra characters or comments: valid JSON contains a single value; comments (
//) are not supported.
Tips
When committing JSON config files to version control (git), consistent indentation makes diffs easier to review. For API payloads traveling over the network, minified JSON uses fewer bytes. A common workflow is to keep beautified JSON for readability during development and switch to the minified form for performance in production.
Frequently Asked Questions
How does the JSON formatter work?
The text you enter is parsed with your browser's native JSON.parse function, then re-serialized with the indentation you choose (2 spaces, 4 spaces or tab). Everything runs in your browser and your data is never sent to a server.
What does JSON minify do?
Minifying removes all unnecessary whitespace, indentation and line breaks, collapsing the JSON onto a single line. This reduces the size of API responses and config files for faster transfer.
How do you locate JSON errors?
When validation fails, the parser's error message is shown. Where possible the approximate line and column of the error is also calculated and displayed, so you can quickly find a missing comma, trailing comma or quoting mistake.
Is my data safe?
Yes. The tool runs 100% in your browser. Your JSON is never uploaded, stored or shared with third parties.