JSON Repair — Fix Common JSON Errors
Fix broken JSON instantly — auto-repair trailing commas, single quotes, unquoted keys, JS comments, Python literals, and unclosed brackets.
What this tool fixes
Trailing commas
{"a": 1,} → {"a": 1}Single quotes
{'key': 'val'} → {"key": "val"}Unquoted keys & values
{name: Al} → {"name": "Al"}JS comments
// comment and /* block */Python literals
True/False/None → true/false/nullUnclosed brackets
{"a": [1, 2 → {"a": [1, 2]}Control characters
Raw newlines/tabs in strings → \n \tAbout JSON Fixer
Need to fix JSON online? The JSON Fixer automatically detects and repairs common JSON syntax errors so you don't have to hunt through malformed data manually. Whether you copied a JavaScript object literal with trailing commas, a Python dict with single quotes and True/False/None, a config file with comments, or received a truncated API response — paste it here and get valid JSON back in one click. Every fix is listed so you know exactly what was wrong and what changed.
How to Use JSON Fixer
Paste Broken JSON
Paste malformed or invalid JSON into the left editor, or click one of the example buttons to load a broken sample.
Click Repair
Click "Repair JSON" — the tool analyzes your input and applies all relevant fixes automatically.
Review Fixes
A list of every change made is shown below the editors so you understand exactly what was wrong.
Copy Fixed JSON
Click Copy to copy the valid, formatted JSON to your clipboard.
Common Use Cases
Copied from JavaScript source
JS object literals use unquoted keys and trailing commas — both invalid in JSON. Paste and repair instantly.
Python dict to JSON
Python dicts use single quotes and True/False/None instead of JSON's true/false/null. Fixed automatically.
Config files with comments
JSONC or hand-edited configs often contain // comments. Strip them out and get valid JSON.
Truncated API responses
Large API responses sometimes get cut off mid-way. The auto-close feature appends missing brackets.
Legacy system exports
Old systems sometimes export malformed JSON. Repair before processing with your pipeline.
Key Features
Trailing comma removal (objects and arrays)
Single quote to double quote conversion
Unquoted key detection and quoting
JS single-line and block comment stripping
Python/Ruby literal normalization (True/False/None)
Auto-close unclosed brackets and braces
Per-fix audit log — see exactly what changed
100% client-side — your JSON never leaves the browser
100% Client-Side Processing
Your data never leaves your browser
All processing happens in your browser using JavaScript. Your data is never sent to our servers or any third party. Safe for sensitive data, API keys, and production configs.
Frequently Asked Questions
Quick answers to common questions about json fixer
No. All repair logic runs entirely in your browser using JavaScript. Your data never leaves your device.
The tool shows a warning with the remaining error message. It still applies all fixable issues so you have less to fix manually.
Missing commas between properties are harder to auto-detect without ambiguity. The tool focuses on the most common and safely automatable fixes.
JSON validation tells you what is wrong. JSON repair actually fixes the issues and returns valid JSON. Use the JSON Schema Validator for schema-level validation.
Yes — JSONC is a common format used in VS Code configs (settings.json, tsconfig.json). This tool strips comments and returns pure valid JSON.