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JSON Formatter

Paste raw, minified, or messy JSON. Get pretty-printed, validated output instantly — runs entirely in your browser, nothing uploaded.

  • Runs in browser
  • No signup
  • No tracking
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How to use JSON Formatter

  1. Paste your JSON into the input pane (or drop a file).

  2. Pick indentation: 2 spaces, 4 spaces, or tabs.

  3. Click Format to pretty-print, or Minify to strip whitespace.

  4. Copy the result or download as a .json file.

When to use it

  • Debugging an API response that breaks your client.

  • Cleaning up minified JSON from a network tab dump.

  • Validating a config file before committing it.

  • Comparing two payloads after diffing keys.

  • Shrinking JSON for storage in a cookie or query string.

What it fixes

  • Cryptic parse errors that don't tell you which line broke.

  • Pasting JSON into another tool and worrying it gets logged.

  • Spending minutes hunting a missing comma in a giant payload.

  • Online formatters that crash on files larger than a few MB.

  • Tools that quietly rewrite your data (key order, number precision).

About JSON Formatter

JSON (JavaScript Object Notation) is the de facto data interchange format for APIs, configuration files, and structured logs. One bad bracket or trailing comma will break a deploy at 2am — that is what this tool catches.

Under the hood it uses the browser's native JSON parser. That means strict spec compliance, fast parsing of multi-megabyte payloads, and zero network round-trips. Errors include the exact line and column, so you can find the byte that broke your config.

References: MDN — JSON.parse · RFC 8259 — JSON spec

Frequently asked

  • Is my JSON sent to a server?

    No. All formatting and validation happens in your browser. Your data never leaves your device.

  • What's the file size limit?

    5 MB on the free tier. Pro users can format files up to 50 MB.

  • Does it support comments or trailing commas?

    Strict JSON does not allow comments or trailing commas. Use the lenient mode (Pro) to clean these before parsing.

  • Can I customize indentation?

    Yes — choose 2 spaces, 4 spaces, or tabs. Defaults to 2 spaces.

Discussion

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