Auto-fix broken JSON data — remove trailing commas, convert single quotes, add missing quotes, strip comments and more. Pure frontend, no server uploads.
Zero Dependencies·Works OfflineThe JSON Repair Tool is a free online tool designed to automatically fix broken or malformed JSON data. Whether you're extracting JSON from log files, editing configuration files by hand, or dealing with abnormal API responses, this tool quickly detects and fixes common JSON syntax errors. All processing happens locally in your browser — your data is never uploaded to any server.
{a:1,} → {"a":1})1. Paste JSON: Paste your broken JSON data into the input area. The tool will auto-detect potential issues.
2. Click Repair: Click the "🔧 Repair" button to automatically detect and fix all recognizable JSON syntax errors.
3. Review Log: After repair, check the repair log to see exactly what was fixed.
4. Copy Result: Click "📋 Copy Result" to copy the repaired JSON to your clipboard, or "💾 Download" to save as a file.
When an API returns malformed JSON, paste it directly into this tool for one-click repair. Quickly restore data usability without manually hunting for syntax errors line by line.
Common errors when editing JSON config files — trailing commas, leftover comments — are automatically fixed, preventing configuration parsing failures.
JSON data from log files, database exports, or third-party sources often contains formatting issues. Batch repair makes the data usable again.
JSON (JavaScript Object Notation) is a lightweight data interchange format with strict requirements: keys must use double quotes, strings must use double quotes, trailing commas are not allowed, and comments are not permitted. However, many real-world scenarios produce JSON that doesn't fully comply — JavaScript object literals allow single quotes and trailing commas, and config files often contain comments. The JSON Repair Tool's core value is automatically converting these "loose formats" into strictly compliant JSON that standard parsers can process correctly.
It can auto-fix common JSON errors: trailing commas, single quotes instead of double quotes, unquoted keys, comments (// and /* */), Unicode escape errors, missing closing brackets/braces, extra escape characters, and more. A detailed repair log shows exactly what was fixed.
Completely safe. All repair operations run locally in your browser. Your JSON data never leaves your device. Even if it contains API keys, database credentials, or other sensitive information, you can use this tool with confidence. Unlike server-based tools, this tool has zero data uploads.
As a pure frontend tool, it's limited by browser memory. Generally supports JSON files up to 10MB. For very large files, consider splitting them first. The browser may briefly lag when processing very large files, which is normal.
If auto-repair cannot fully fix the JSON, the tool will show the specific error location and reason. You can manually fix the key errors and try again. For severely damaged JSON, we recommend manually fixing critical errors first, then using this tool for remaining issues.
A JSON validator only detects and reports errors without fixing them. This JSON repair tool automatically fixes detected issues and outputs valid JSON. For best results, use both: repair first, then validate to confirm the result.