jsonpost
Formatting & Validation

JSON Validator / Lint

Validate JSON against the official specification and catch syntax errors with exact line and column numbers.

Runs entirely in your browser — your data never leaves your device.

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How to use this tool

  1. 1Paste the JSON you want to check into the editor.
  2. 2See an instant valid/invalid verdict.
  3. 3If invalid, read the exact line, column, and description of the error.

Frequently asked questions

What does the validator check?
It validates against the JSON specification (RFC 8259): matching brackets, proper quoting, valid escape sequences, no trailing commas, and correct value types.
How do I fix the errors it finds?
Each error includes a line and column number and a description. For automatic repair of common mistakes, try the JSON Fixer tool.
Is my data uploaded to a server?
No. Every tool on JSONPost runs entirely in your browser using JavaScript. Your JSON never leaves your device, so it is safe to use with private or sensitive data.

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