developer toolsSyntax Error Finder

JSON Validator & Syntax Linter

Find and fix JSON parsing errors instantly. Pinpoints missing quotes, unclosed braces, unexpected trailing commas, and formatting discrepancies.

Validated locally in your browser. Code is never transmitted to servers.
Indent:
INPUT (JSON)
OUTPUT (JSON)
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How to Use JSON Validator & Linter

1

Paste JSON

Paste your raw JSON string or upload a .json file.

2

Inspect Errors

Review highlighted syntax errors with exact line and column coordinates.

3

Autofix & Copy

Click Autofix or Format to clean and copy the valid JSON.

About JSON Validator & Linter

Parses input strings through iterative recursive-descent syntax tree analysis, intercepting SyntaxError exceptions and mapping character offsets to line/column coordinates.

Supported Formats

JSONJSONC

Operational Limits

  • Standard JSON schema; does not evaluate arbitrary JavaScript objects

Key Features

  • Exact line and column error reporting
  • Detects trailing commas and unquoted keys
  • Format with 2 or 4 spaces
  • One-click copy and JSON download

Frequently Asked Questions

Common JSON syntax errors include single quotes instead of double quotes, trailing commas after the last array/object item, and missing property colons.