Format, validate and minify any JSON string in one click. Catch syntax errors instantly, beautify minified payloads for readability, or compress formatted JSON back to a single line. Runs entirely in your browser.
JSON (JavaScript Object Notation) is the universal data exchange format for APIs, configuration files, and front-end state. When debugging, you often receive minified one-line JSON that's nearly unreadable — or hand-typed JSON with a missing comma that breaks parsing. A formatter beautifies the structure with proper indentation; a validator catches syntax errors precisely; a minifier compresses formatted JSON back to one line for transmission.
Paste your JSON into the textarea. Click Format & Validate to pretty-print with 2-space indentation and confirm the syntax is valid. Click Minify to strip all whitespace for a compact one-line version. Errors point to the exact character position so you can fix them quickly.
Use it when debugging API responses, when writing configuration files (package.json, tsconfig.json, GitHub Actions workflows), when copying JSON between systems, when troubleshooting webhook payloads, and when reviewing exported data from analytics or BI tools.
Keep formatted JSON for development and minified JSON for production transmission. Use JSON Schema for validation beyond syntax — it checks structure and types. For very large JSON files (over 10MB), browser parsing may slow down — use a desktop tool like jq instead.
Common culprits: trailing commas (not allowed in JSON), single quotes instead of double, unquoted keys, and Unicode invisible characters from copy-paste. The error message points to the position.
JSON requires double-quoted keys and string values, no trailing commas, no comments, no functions. JavaScript objects are looser.
Browser memory limits practical JSON to a few hundred MB at most. For larger files use jq or a streaming parser.
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