Fix Invalid JSON Online
Paste broken JSON and get it fixed automatically. Handles trailing commas, single quotes, comments, unquoted keys and other common syntax mistakes.
Working with Broken JSON
Strategies for handling JSON files that fail validation.
Use Auto-Fix Before Manual Editing
The auto-fix handles over 90% of common errors. Try it first — if issues remain, the validator will pinpoint the exact location of each remaining error for manual correction.
Watch for JavaScript vs JSON Differences
If your JSON came from a JavaScript file, expect single quotes, trailing commas, and unquoted keys. The auto-fix handles all three in one pass.
Check Encoding for Invisible Characters
Some JSON errors come from invisible Unicode characters (BOM, zero-width spaces) copied from rich-text editors or PDFs. If auto-fix does not resolve the error, paste into a hex editor to find hidden characters.
Validate After Every Fix
After applying auto-fix, re-validate to confirm all errors are resolved. Some fixes can reveal previously hidden errors deeper in the structure.
JSON Auto-Repair
Automatically fix the most common JSON syntax errors without manual editing.
One-Click Auto-Fix
Click the fix button to repair trailing commas, single quotes, JavaScript comments and unquoted keys in one pass. No manual editing required.
Precise Error Location
See the exact line and column of every syntax error with descriptive messages. Jump directly to the problem instead of scanning thousands of lines.
Side-by-Side Comparison
Compare the original broken JSON with the fixed version to verify every change before copying the result.
Why JSON Validation Matters
Invalid JSON breaks APIs, crashes applications and causes silent data loss. A single trailing comma that works in JavaScript will cause JSON.parse() to throw in production. Validating and fixing JSON before deployment prevents these runtime failures.
Prevention Tips
Always validate JSON output before sending it to APIs or saving to files
Configure your IDE to flag JSON syntax errors in real time
Use a JSON linter in your CI/CD pipeline to catch errors before deployment
Fix Invalid JSON — FAQ
What are the most common JSON syntax errors?
The five most common errors are: (1) trailing commas after the last item in an array or object, (2) single quotes instead of double quotes, (3) JavaScript-style comments (// or /* */), (4) unquoted property keys, and (5) missing commas between elements.
Can this tool fix all JSON errors?
It fixes the most common structural errors automatically. Issues like mismatched braces, fundamentally broken structure, or truncated files may need manual correction. The error messages will guide you to the exact location of any remaining issues.
Why does JSON not allow trailing commas?
The JSON specification (RFC 8259) requires strict syntax — no trailing commas, no comments, double quotes only. This is intentional: JSON is a data interchange format, not a programming language, and strict rules prevent ambiguity between parsers.
How do I fix 'Unexpected token' errors?
An 'Unexpected token' error means the parser found a character it did not expect at a specific position. Common causes: a comma after the last element, a single quote, a comment, or a missing closing bracket. This tool highlights and auto-fixes these issues.
Can I use comments in JSON?
Standard JSON does not support comments. If your config file needs comments, consider JSONC (JSON with Comments, supported by VS Code) or JSON5. This tool can strip comments from JSONC to produce valid JSON.
Why is my JSON from JavaScript invalid?
JavaScript object literals allow unquoted keys, trailing commas, single quotes and comments — none of which are valid JSON. When you copy a JS object to use as JSON, these differences cause parse failures. This tool converts JS-style objects to strict JSON.
Is the fixed JSON identical to my original data?
Yes for data content. The auto-fix only changes syntax (quote style, removes comments, fixes commas) — it never changes actual values, keys, or the structure of your data.
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