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JSON Formatter & Validator

Professional developer utility to format, validate, and minify JSON with precise line/column syntax error detection and payload size statistics.

100% Client-Side JSON Processing: Your JSON is validated, beautified, and minified in browser memory without reaching any server.
Indent:
Input JSON151 chars
Formatted / Minified Output0 chars

What "Valid" Means Before Anything Formats

JSON tolerates zero mistakes: a trailing comma, a single-quoted string, or a comment all fail the parser, and every formatter — including this one — refuses the input instead of guessing. That refusal is the feature: format-then-fix hides errors, validate-first surfaces them with their position.

The minify side matters beyond aesthetics: a 40 KB config pretty-printed with 2-space indents drops 30–50% once whitespace is stripped, and APIs charge or throttle by transferred bytes. Formatting for humans, minifying for machines, and keeping both buttons on the same screen is the whole workflow.

What the Formatter Changes

  1. Paste any JSON payload — from an API response, a config file, or a log line.
  2. The validator parses the text and reports syntax errors with exact line and column positions instead of a generic failure.
  3. Choose Format to beautify with 2-space indentation, or Minify to strip all whitespace for transport.
  4. Size statistics show the original vs. minified byte count, and you can copy or download the result.

Example Input and Output

Beautify an API response
Input: {"id":1,"user":{"name":"Ana","active":true},"tags":["a","b"]}
Output: Pretty-printed object tree
Reading an indented response makes debugging API integrations dramatically faster, especially for nested objects.
Locate a trailing comma error
Input: {"a":1,"b":2,}
Output: Error at line 1, column 11 — trailing comma
Trailing commas are valid in JavaScript but invalid in JSON. The precise position lets you fix it in seconds.

Common Questions

Why is a line/column error useful?

Most JSON tools just say "invalid JSON". Reporting the exact position turns debugging from guessing into a one-line fix.

Does it validate schema or just syntax?

It validates syntax and structural correctness. JSON Schema validation (required fields, types) is not performed.

Is my JSON sent anywhere?

No. Parsing and formatting run entirely in your browser, so confidential API responses never leave your machine.

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