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Free JSON Formatter Online

A free JSON formatter: format, validate, and minify JSON instantly — with precise error messages and zero sign-up.

Free tool · No sign-up · Private

JSON input

Private by design. Everything runs 100% in your browser — your JSON is never uploaded, stored, or sent anywhere.

About this tool

About the JSON Formatter

A JSON formatter takes the unreadable one-line blob your API returned and turns it into clean, indented, human-readable JSON. Paste any JSON into this free online tool and it validates the structure, pretty-prints it with proper indentation, or minifies it down for production payloads. Developers debugging APIs, configuring n8n workflows, and editing config files use it daily — and when your JSON is broken, the error messages point at the exact line and character instead of a cryptic failure.

Common culprits like trailing commas, unquoted keys, and mismatched brackets get flagged with plain-language explanations, which makes this as much a learning tool as a utility. Everything runs in your browser, so API keys, tokens, and production payloads you paste are never sent to a server. Switch between formatted and minified views with one click, copy the result straight to your clipboard, and get back to building.

How it works

Three steps to clean JSON

Paste your JSON

Drop in an API response, config file, or payload — formatted or minified, valid or broken.

Pick an action

Format for readable indentation, Minify for the smallest payload, or Validate to just check syntax.

Fix or copy

Errors show the exact line and column with a caret. Copy the fixed result straight into your code.

Good to know

Features built in

What the tool does for you, and the limits it respects.

Pretty-print & minify

Format expands JSON to readable 2-space indentation; Minify compresses it to a single line. Both preserve key order and all values exactly.

Errors with line numbers

Instead of a cryptic message, you get the line, the column, and the offending line with a caret — so a missing comma takes seconds to find.

Strict JSON rules

Validation follows the JSON spec: double quotes only, no trailing commas, no comments, no NaN or Infinity. If it passes here, JSON.parse accepts it anywhere.

Local & unlimited

No uploads means no size caps and no waiting on a server. Large API dumps format instantly, and your data never leaves the tab.

Examples

Common fixes

trailing-comma.json

{ "name": "YATools",
  "free": true,   ← trailing comma
}

Error: line 2, column 17.
Remove the comma → valid.

minify.json

Before: 1,240 chars, indented
After minify: 812 chars, one line

Smaller payloads = faster API
calls and cheaper bandwidth.

FAQ

JSON questions

What does the JSON formatter do?

It takes raw JSON — however messy — and reprints it with clean 2-space indentation so the structure is easy to read. Minify does the opposite: it strips all whitespace for the smallest possible payload. Validate just checks the syntax without changing anything.

How do I find the error in my JSON?

Paste it and hit Format or Validate. If parsing fails, the tool shows the exact line and column plus the offending line with a caret pointing at the problem. The most common culprits are trailing commas, single quotes instead of double quotes, and unquoted keys.

Why does my JSON fail with “Unexpected token”?

Strict JSON is pickier than JavaScript objects: keys and strings must use double quotes, trailing commas are forbidden, and comments are not allowed. Copy the reported line/column from the error box and fix that spot.

Is there a size limit?

No server-side limit — everything runs in your browser, so even multi-megabyte API responses format fine. Extremely large documents (tens of MB) may take a moment to render.

Is my JSON data private?

Yes. Parsing and formatting happen locally on your device; your JSON is never uploaded or logged. Safe for API keys, tokens, and production payloads — though as a rule, avoid pasting live secrets anywhere.

Is there a free JSON formatter with no sign-up?

Yes. Paste your JSON and get formatted, validated output instantly — no account, no upload, and your data never leaves your browser.

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