QuietJSON

Fix Broken JSON Online — Free JSON Repair Tool

Paste your JSON below and click 🔧 Repair — trailing commas, single quotes, unquoted keys, LLM output all fixed instantly.

Our tool automatically detects and corrects the most common JSON errors — includingtrailing commas, single quotes,unquoted keys, JavaScript-style comments, and Python-style True/False/None values.

Specifically designed to fix JSON output from ChatGPT, Claude, Gemini, or any LLM. AI models are great at generating content but often produce slightly malformed JSON — a trailing comma here, single quotes there. Instead of manually hunting for the error, paste it here and let the repair engine fix it in milliseconds. The pre-filled example above shows exactly the kind of LLM output this tool excels at fixing.

All processing is 100% browser-based — your JSON never leaves your device. No server uploads, no accounts, no size limits. Works entirely offline after the page loads. Need to validate, format, or explore your fixed JSON as a tree? Use the Format and 🌳 Tree buttons after repairing.

How it works

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STEP 1
Paste
Paste your broken JSON into the input panel — or drag & drop a .json file.
🔧
STEP 2
Click Repair
Click the amber Repair button. Errors are auto-detected and fixed instantly.
✅
STEP 3
Copy & Use
Copy the fixed JSON or download it. Switch to Tree view to explore the structure.
Need the full JSON formatter, validator, and tree viewer?Try our main JSON tool →

Frequently Asked Questions

Why is my JSON invalid or broken?+

JSON parsing errors typically occur due to subtle syntax mistakes. The most common issues include trailing commas after the last item, single quotes instead of double quotes around strings, unquoted object keys, JavaScript comments, or Python constants like True, False, or None.

Can this tool fix JSON copied from ChatGPT or other AI tools?+

Yes. Large language models like ChatGPT, Claude, and Gemini frequently generate conversational JSON containing markdown wrappers, trailing commas, single quotes, or missing brackets. QuietJSON's repair engine is specifically optimized to fix these common AI output issues.

What kinds of errors can the repair tool fix?+

The repair tool automatically fixes unquoted keys, trailing commas in objects and arrays, single-quoted strings, JavaScript comments (// and /* */), Python boolean/null constants, missing closing brackets, and misplaced string escapes.

Will repairing change my actual data/values?+

No. The repair algorithm only corrects the surrounding syntax and formatting required to make the JSON specification-compliant. It preserves your original keys, string contents, numeric values, and object structures without altering your underlying data.