JSON Repair Tool Online — Fix Broken JSON Instantly
Repair malformed JSON in seconds. Free AI-powered JSON repair tool — fix trailing commas, missing quotes, syntax errors, and truncated JSON instantly. No signup, no install.
10 error types repaired automatically
JSON Errors This Tool Repairs
Paste any broken JSON and get valid, formatted output in under one second. Every repair is explained in plain English.
Trailing commas after the last element are not valid JSON
JSON requires double quotes — single quotes are invalid
All object keys must be double-quoted strings in JSON
Streaming API responses cut off at token limits are completed
Python True/False/None converted to JSON true/false/null
Markdown code blocks wrapping JSON are stripped automatically
JavaScript // and /* */ comments are removed from JSON
NaN, Infinity, and undefined replaced with valid JSON null
Tool comparison
Why AI JSONMedic is the Best JSON Repair Tool
Most tools just validate. AI JSONMedic actually repairs — and explains every fix.
| Feature | AI JSONMedic | JSONLint | jsonrepair.com | buildertools |
|---|---|---|---|---|
| Actually repairs JSON (not just validates) | ✓ | ✗ | ✓ | ✗ |
| Trailing comma removal | ✓ | ✗ | ✓ | ✓ |
| Single-quote conversion | ✓ | ✗ | ✓ | ✓ |
| Python boolean fix (True/False/None) | ✓ | ✗ | ✗ | ✗ |
| Markdown code fence stripping | ✓ | ✗ | ✗ | ✗ |
| Truncated JSON completion | ✓ | ✗ | ✓ | ✗ |
| JavaScript comment removal | ✓ | ✗ | ✓ | ✗ |
| Plain-English repair explanations | ✓ | ✗ | ✗ | ✗ |
| Before/after diff view | ✓ | ✗ | ✗ | ✗ |
| Public REST API | ✓ | ✗ | ✗ | ✗ |
| No signup required | ✓ | ✓ | ✓ | ✓ |
| Free to use | ✓ | ✓ | ✓ | ✓ |
Comparison based on publicly available tool features as of 2026.
What is a JSON Repair Tool?
A JSON repair tool automatically identifies and fixes syntax errors in broken or malformed JSON data. Unlike a JSON validator — which only tells you that your JSON is invalid — a repair tool actually corrects the errors and returns valid JSON you can use immediately.
Common JSON errors that require repair include trailing commas after the last array or object element, single quotes instead of double quotes, unquoted object keys, missing commas between values, Python-style boolean literals (True, False, None), and truncated JSON structures where the data was cut off before completion.
How to Repair JSON Online
Using this free JSON repair tool is straightforward:
- Paste your broken or malformed JSON into the input box above
- Click Fix JSON or press Ctrl+Enter
- The repaired JSON appears instantly in the output panel
- Review the plain-English repair report to understand what was fixed
- Copy the fixed JSON or download it as a file
All processing happens in your browser — your JSON data is never uploaded to any server. The tool handles documents up to 2MB and completes repairs in under one second.
JSON Repair vs JSON Validation: What's the Difference?
JSON validation checks whether your JSON is syntactically correct according to the JSON specification (RFC 8259). It returns a pass or fail result with an error message pointing to the problem location.
JSON repair goes further: it takes invalid JSON and transforms it into valid JSON by applying a series of targeted fixes. AI JSONMedic runs a 14-stage repair pipeline that handles every common JSON syntax error, then validates the result to confirm the repair succeeded.
For most real-world use cases — especially when working with AI-generated output, API responses, or data from automation tools — you need repair, not just validation. Tools like JSONLint can tell you something is wrong; they cannot fix it for you.
Most Common JSON Repair Scenarios
The most frequent reasons developers need to repair JSON online include:
- AI-generated JSON — ChatGPT, Claude, and Gemini frequently produce JSON wrapped in markdown code fences, with trailing commas, or using Python-style booleans
- Streaming API responses — LLM responses cut off at token limits leave unclosed brackets and strings
- Hand-edited JSON — developers editing JSON by hand often introduce trailing commas or miss closing brackets
- n8n and Make.com workflows — automation platforms produce JavaScript object literals with single quotes and unquoted keys
- Data pipeline output — Python scripts frequently serialize data using Python literals instead of JSON-compliant values
- Copy-paste errors — JSON copied from documentation, Slack, or emails often picks up encoding artifacts and formatting issues
Why Choose AI JSONMedic for JSON Repair?
AI JSONMedic is the only JSON repair tool built specifically for the failure patterns produced by AI language models and modern automation tools. While generic JSON repair utilities handle basic syntax errors, they fail on AI-specific issues like markdown wrapping, Python literals, and streaming truncation.
Every repair is fully transparent: the tool shows you exactly what changed with a diff view and explains each fix in plain English. You always understand what was wrong and why the fix is correct — it is not a black box.
The tool is free with no account required. For teams that need automated JSON repair at scale, the REST API accepts raw JSON via POST and returns repaired output with a full repair report.
JSON Repair Tool — Frequently Asked Questions
What is a JSON repair tool?
A JSON repair tool automatically detects and fixes syntax errors in broken or malformed JSON. It corrects issues like trailing commas, missing quotes, single quotes, unquoted keys, and truncated structures so your JSON passes validation.
How do I repair JSON online for free?
Paste your broken JSON into the tool above and click "Fix JSON". AI JSONMedic will instantly repair all syntax errors and display the valid, formatted result. It is completely free with no account required.
What types of JSON errors can this tool repair?
AI JSONMedic repairs: trailing commas, missing commas, single quotes, unquoted keys, Python booleans (True/False/None), NaN/Infinity/undefined values, JavaScript comments (// and /* */), markdown code fences, BOM characters, and truncated/incomplete JSON structures.
Is this JSON repair tool better than JSONLint?
Yes — JSONLint only validates JSON and tells you it is broken. AI JSONMedic actually repairs the JSON, explains every fix in plain English, and handles AI-specific error patterns like markdown wrapping and Python literals that JSONLint cannot fix.
Does the JSON repair tool store my data?
No. All JSON repair happens entirely in your browser using client-side JavaScript. Your JSON data never reaches any server. Nothing is stored, logged, or transmitted.
Can it repair JSON from AI tools like ChatGPT or Claude?
Yes. AI JSONMedic is specifically built for AI-generated JSON. It handles all common LLM output errors: markdown code fences, trailing commas, Python-style booleans, single quotes, and truncated streaming responses.
What is the maximum JSON size for repair?
The JSON repair tool handles documents up to 2MB. For larger files, split the JSON into sections before pasting, or use the /api/repair API endpoint directly.
Is there an API for automated JSON repair?
Yes. Send a POST request to /api/repair with your JSON in the request body. The API returns the repaired JSON along with a full repair report. See the API documentation for examples.
JSON Repair Guides
In-depth guides for the most common JSON errors developers encounter: