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JSON Validator - Free Online Tool

Paste JSON to check if it is valid. Invalid input shows the parser error and, when available, line and column so you can fix it.

Validate JSON

How to Use This Tool

  1. Paste your JSON into the input box.
  2. Click Validate to check syntax.
  3. If invalid, read the error message and line/column to fix the issue.

Benefits of Using This Tool

  • Instant validation with clear error messages.
  • Line and column info when the parser provides it.
  • Runs in your browser; no data sent to servers.

When to Use JSON Validator

  • Check API response or config files before use.
  • Debug JSON syntax errors quickly.
  • Verify user input or generated JSON.

Decision Guide

Best for

  • Pre-checking JSON before feeding it into scripts or CI pipelines.
  • Catching syntax mistakes in generated output from AI/tools.
  • Quickly isolating invalid characters in long payloads.

Avoid when

  • You need schema validation against required fields or data types.
  • You need semantic checks (for example, date ranges or unique IDs).

Example

Detect invalid trailing comma

Input

{
  "name": "Rohan",
  "role": "admin",
}

Output

Unexpected token } in JSON at position 38

Trailing commas are allowed in some JS contexts but invalid in JSON.

Troubleshooting

Validator fails but the payload looks correct.

Look for hidden characters copied from docs/chat apps. Re-type quotes and line breaks around the error location.

Error line number does not match your editor.

Ensure the exact payload is pasted without extra prefixes, comments, or wrapped text.

FAQs

What counts as valid JSON?

Valid JSON uses double quotes for strings, no trailing commas, and only the allowed types: object, array, string, number, boolean, null.

Is my JSON sent to a server?

No. Validation runs entirely in your browser. Your data never leaves your device.

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