Format, validate, minify, and inspect JSON with clear syntax errors and privacy-first browser processing.
Quick answer: Paste JSON, choose an indentation size, and press Format. The tool validates the syntax, shows the exact parse error when possible, and produces readable or minified JSON locally in your browser.
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How this json formatter helps
This free online JSON formatter helps developers and data teams validate API responses, configuration files, webhook payloads, and structured logs without sending sensitive data to a server. Paste raw JSON or load a sample, then format it with two or four spaces, minify it for transport, sort object keys, or inspect the validation error in plain language. The parser reports the line and character whenever the browser exposes that information, making it easier to find a missing comma, trailing comma, unquoted property, or broken string. Because all work is performed by JavaScript on your device, the payload never leaves the page. You can also save recent work locally, copy the result with one click, download it as a .json file, and enable Pro mode to process multiple JSON files in one batch. It is useful for frontend debugging, backend API checks, CI configuration review, documentation examples, and quick data cleanup when a full IDE would be unnecessary.
Last updated: . All processing happens locally; no tool input is sent to a server.
Real-world examples
Debug an API response
Paste a compact REST or GraphQL response and format it before checking nested fields.
Validate configuration
Check package, application, or infrastructure configuration before committing it.
Prepare a payload
Minify a hand-edited request body and copy it into an API client.
Embed this tool
Add a compact version to documentation or an internal wiki. The attribution link helps other developers find the full tool.
Frequently asked questions
Is this JSON formatter free and private?
Yes. Formatting and validation run entirely in your browser. Your input is not uploaded to a server by this tool.
Why does my JSON fail to parse?
Common causes include trailing commas, single quotes, comments, unquoted keys, and missing commas. JSON is stricter than JavaScript object syntax.
Can I minify JSON for an API request?
Yes. Use the Minify action after validating the document to remove unnecessary whitespace while preserving its data.
Can this tool process large files?
It can handle reasonably large files, but browser memory limits still apply. Very large logs are usually better handled by a desktop editor or command-line parser.