JSON Linter & Formatter
Paste or type JSON, validate it instantly, and format or minify it in your browser. Copy the result to your clipboard or download it as a .json file with no uploads or accounts required.
JSON is processed entirely in your browser.
Paste sensitive data only if you are comfortable keeping it in this browser tab. Nothing is sent to a server; validation and formatting happen locally using your device.
JSON input
Formatted output
Work with JSON safely in your browser
JSON (JavaScript Object Notation) is a lightweight format for representing structured data. It powers most modern web APIs, configuration files, and many logging formats. You see it when you work with REST endpoints, front‑end state, or cloud provider settings. Because JSON is strict about commas, quotes, and braces, a single typo can make a whole payload invalid.
Common JSON mistakes this tool can help catch
When editing JSON by hand, a few problems show up over and over:
- Trailing commas. JSON does not allow a comma after the last item in an array or object.
- Unquoted keys. Object keys must be wrapped in double quotes, not left bare like in some JavaScript code.
- Single quotes. JSON requires double quotes around strings; single quotes cause parse errors.
- Mismatched braces or brackets. Missing a closing
}or]can be hard to see in long payloads.
The linter highlights invalid JSON and reports an error with a line and column number so you can jump directly to the problem. Once your JSON is valid, the formatter can pretty‑print it with 2‑ or 4‑space indentation, or minify it down to a single line for use in query strings or compact config values.
Why a client‑side JSON tool matters for privacy
Many JSON linters send your data to a remote server for validation. That can be a problem if you are working with production API responses, internal configuration, or anything that contains customer data. This tool runs entirely in your browser: parsing, formatting, and error reporting all happen locally using your device's CPU. Nothing is uploaded, so you can safely paste internal payloads without worrying about where they go.
Part of a small set of developer utilities
The JSON Linter & Formatter is designed to pair well with other lightweight developer tools. For example, you can compare two versions of a JSON document with the Diff Checker or use future utilities under a "Developer Tools" section on LifeHackToolbox. All of these tools share the same philosophy: small, focused, privacy‑friendly utilities that you can open in a browser tab and trust.
Because everything runs client‑side, you can use this JSON tool even on slow or locked‑down networks. There are no logins, no telemetry, and no sync process; you simply paste, format, and copy the result. If you find it useful, you can bookmark this page or share it with teammates who regularly debug JSON payloads.