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Fix Invalid JSON Online

Use this page when JSON fails to parse and you need a fast way to identify the syntax problem, repair it manually, and validate the corrected result. It is designed for the “fix invalid JSON” intent, not just formatting.

Paste JSON to begin.
Ctrl or Command + Enter checks JSON. 0 chars
Runs locally in your browser. Your JSON is not uploaded.

What this tool does

This page helps you validate broken JSON and then fix the syntax using clear examples of the mistakes that usually cause parsing failures.

Common use cases

  • Repairing API request bodies before retrying a call.
  • Cleaning copy-pasted JSON from docs, Slack, or log output.
  • Fixing malformed config snippets before deployment.
  • Teaching JSON syntax rules with quick before-and-after examples.

Before and after example

Broken JSON

{ "name": "Ada", "city": "Vilnius", }

Fixed JSON

{
  "name": "Ada",
  "city": "Vilnius"
}

Common JSON errors related to repair

  • Trailing commas at the end of arrays or objects.
  • Single quotes around strings or keys.
  • Missing closing brackets after nested arrays.
  • JavaScript-style comments inside otherwise valid JSON.

How to use the tool

  1. Paste the invalid JSON into the editor.
  2. Click Check JSON Errors to confirm the payload is invalid.
  3. Remove the syntax issue, then validate again.
  4. Format the corrected JSON so the final result is easy to review and reuse.
Privacy note: Runs locally in your browser. Your JSON is not uploaded.

Related JSON tools

JSON Validator

Validate syntax quickly while staying in the same debugging cluster.

FAQ

Does this tool automatically rewrite invalid JSON?

No. It validates JSON and supports a manual repair workflow, which is more trustworthy than claiming perfect auto-fixes for every broken payload.

What is the fastest error to check first?

Look for trailing commas, single quotes, comments, and missing closing braces or brackets.

Can I upload a bad JSON file to inspect it here?

Yes. Upload a local file and the page will load it directly in your browser.

Where should I go after fixing the syntax?

Use JSON Formatter or JSON Pretty Print Online to clean up the final output.