Format, beautify, validate, compare, and minify JSON data
Transform minified or poorly formatted JSON into clean, indented output. Choose between 2, 4, or 8 space indentation to match your project standards.
Instantly detect JSON syntax errors with precise line numbers and character positions. Get clear error messages that explain exactly what went wrong and where.
Strip all whitespace, line breaks, and indentation to produce the smallest possible JSON output. Reduces payload size for API responses and configuration files.
Compare two JSON structures side-by-side with semantic diff detection. Understands JSON structure to identify added, removed, and modified values — not just text changes.
Automatically repair common JSON issues: trailing commas, missing quotes, single quotes, Python True/False/None values, JavaScript comments, and more.
Sort keys alphabetically, remove null or empty values, flatten nested structures, generate TypeScript interfaces, and decode Base64 or URL-encoded JSON.
Format API responses for debugging, validate request payloads before sending, and compare API versions to catch breaking changes.
Validate package.json, tsconfig.json, and other config files. Catch syntax errors before they cause build failures.
Beautify raw JSON data dumps for inspection. Flatten nested structures for easier processing and extract specific fields.
Compare JSON fixtures, mock data, or config changes between branches. Semantic diff highlights meaningful changes, not formatting noise.
Format single-line JSON log entries for readability. Validate structured logging output and inspect complex nested payloads.
Format MongoDB documents, CouchDB exports, or any JSON-based database output for human review and documentation.
Unlike other online JSON formatters that upload your data to servers, our tool processes everything locally in your browser using JavaScript. Your JSON data — including API keys, credentials, and personal information — never leaves your device.
Paste your JSON into the input panel and click 'Format / Beautify'. The tool adds proper indentation and line breaks instantly. You can choose 2, 4, or 8 space indentation. The formatted result can be copied or downloaded as a .json file.
Paste your JSON and click 'Validate'. The tool checks for syntax errors and displays detailed error messages with the exact line number and character position. Common errors include missing commas, unquoted keys, and trailing commas.
Formatting (beautifying) adds indentation and line breaks to make JSON human-readable. Minification removes all unnecessary whitespace to reduce file size. Use formatting during development for readability, and minification in production to save bandwidth.
Yes. Switch to Compare mode using the toolbar. Paste JSON into both panels and the tool highlights differences using semantic comparison — it understands JSON structure rather than just comparing text line by line.
Yes. All processing happens 100% in your browser using JavaScript. Your JSON data is never sent to any server. This makes it safe for formatting JSON containing API keys, credentials, or other sensitive information.
Yes. If the validator detects fixable errors (trailing commas, missing quotes, single quotes, Python True/False/None, comments), a 'Fix JSON' button appears. Click it to automatically repair all detected issues. For more complex repairs, try the dedicated Auto-Fix tool.
Beyond formatting and minifying, the tool can sort keys alphabetically, remove null values, remove empty strings, flatten nested structures, generate TypeScript interfaces, and decode Base64-encoded or URL-encoded JSON.
Yes. After the initial page load, the formatter works entirely offline since all processing runs in your browser. No internet connection is needed to format, validate, or minify JSON.