Format output Show repair log

Features

🔧 Auto-Fix Common Errors

Trailing commas in objects and arrays
Single-quoted strings to double quotes
Unquoted object keys
Missing or extra brackets

📋 Repair Log

See exactly what was fixed
Understand each transformation
Learn common JSON mistakes
Detailed error descriptions

✅ Validation After Repair

Validates result is valid JSON
Pretty-prints the output
Copy or download fixed JSON
Clear error messages if unfixable

JSON Repair Guide

Common JSON Errors Fixed

This tool automatically repairs the most frequent JSON syntax problems:

// ❌ Invalid - trailing commas
{"name": "John", "age": 30,}

// ✅ Fixed
{"name": "John", "age": 30}

// ❌ Invalid - single quotes
{'name': 'John'}

// ✅ Fixed
{"name": "John"}

// ❌ Invalid - unquoted keys
{name: "John", age: 30}

// ✅ Fixed
{"name": "John", "age": 30}

How JSON Repair Works

The repair process applies transformations in a specific order:

Single quotes: Replaces single-quoted strings with double-quoted ones (avoids replacing apostrophes in words)
Unquoted keys: Wraps bare identifiers used as object keys in double quotes
Trailing commas: Removes commas immediately before } or ]
Validation: Attempts JSON.parse() to confirm the result is valid

Common Use Cases

JavaScript Objects: Paste JS object literals and convert them to valid JSON
Config Files: Fix hand-edited JSON configs with trailing commas or comments
API Responses: Repair malformed API responses before processing
Data Migration: Fix exported data with incorrect JSON syntax
Learning: Understand what makes JSON invalid by seeing the fixes

FAQ

Q: Why can't every JSON error be fixed automatically?

A: Some errors like missing commas between elements or deeply corrupted structures are ambiguous — the tool cannot know the intended structure, so it reports the remaining error instead of guessing wrong.

Q: Will repair change my data values?

A: No. The repair only adjusts syntax — keys, values, and data structure remain exactly the same. Only quotes, commas, and brackets are modified.

Preventing broken JSON in the first place

Repairing JSON is a good quick fix, but it is worth finding out why it broke. Most invalid JSON comes from hand editing, string concatenation in code or copying from places that change quotes and whitespace.

Tips and common pitfalls

Always build JSON with a serializer such as JSON.stringify or json.dumps, never by joining strings.
Word processors and chat apps may replace straight quotes with curly ones. Paste into a plain text editor first.
Edit configuration in an editor with JSON validation, such as VS Code, which underlines errors as you type.
If the JSON comes from an AI model, use schema-constrained output or our LLM JSON Extractor, which also strips surrounding text.

JSON Repair & Fixer