What kind of JSON errors can the Auto-Fix feature repair?

It automatically repairs trailing commas, single quotes around strings/keys, unquoted keys, single-line/multi-line comments, and Python literals (True, False, None).

Does this tool support large JSON files?

Yes. With Monaco editor and Web Worker processing, it smoothly handles multi-megabyte JSON documents.

JSON Validator & Fixer

Free online JSON Validator, Linter and Auto-Fixer. Detect syntax errors with line/column accuracy and instantly repair trailing commas, single quotes, comments, and unquoted keys.

100% Private (In-Browser)Instant Web Worker SpeedZero Server Upload

JSON Validator & Fixer by Privacy-First Toolbox is a 100% free, client-side browser utility. It processes your files locally on your computer or smartphone using HTML5 and Web Workers—zero bytes of your files or data are ever uploaded to any external server.

Paste or upload JSON to validate

JSON Document (0 lines)

Key Features

Real-time JSON syntax validation with line & column error markers
One-click Auto-Fix for trailing commas, single quotes, and Python literals
Removal of single-line and multi-line comments
Document metrics: total lines, key count, nesting depth, and byte size
Beautify and Minify tools included

Common Use Cases

Fixing invalid JSON copied from Python dictionaries or JavaScript objects
Finding invisible syntax errors (trailing commas, unescaped quotes) in large files
Validating configuration files before deploying code

Frequently Asked Questions

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Beautify, minify, and validate JSON

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Compare two JSON objects and highlight differences

JSON to CSV

Convert JSON array to CSV

CSV to JSON

Convert CSV to JSON array

JSON to TypeScript

Convert JSON to TypeScript Interfaces

JSON to YAML

Convert JSON to YAML format

YAML to JSON

Convert YAML to JSON format

JSONPath Tester

Test and evaluate JSONPath expressions online

JSON to XML

Convert JSON to XML format online

XML to JSON

Convert XML to JSON format online

JSON to SQL

Convert JSON to SQL INSERT and CREATE TABLE statements

JSON to JSON Schema

Generate JSON Schema from sample JSON

JSON Viewer

Interactive JSON Tree Visualizer & Explorer

JSON Minifier

Compress and minify JSON to reduce payload size

JSON Unescape & Stringify

Unescape stringified JSON or escape JSON into code literals

JSON Sorter

Sort and alphabetize JSON keys recursively