JSON Formatter

1. Paste your raw JSON into the Input JSON box on the left. You can also click Sample to load a valid example.
2. Choose your preferred indentation: 2 spaces, 4 spaces, or a tab character. The default is 2 spaces, which matches the configuration most teams use in .prettierrc.
3. Click Format to pretty-print the JSON, Minify to strip all whitespace (useful for shrinking API responses), or Validate to check whether the input parses without changing it.
4. Copy the result to your clipboard with Copy, or download it as a .json file.

The formatter is fully fault-tolerant: if your input is invalid JSON, the status line under the input will show the exact error message returned by Prettier, including the line and column where the parser failed. Your original input is never modified in place — the formatted output always appears in the right-hand panel, so you can compare them side by side.

JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format defined in RFC 8259. It is the de-facto serialization format for REST APIs, configuration files, NoSQL databases such as MongoDB and DynamoDB, and structured logs. A JSON formatter (also called a beautifier or pretty-printer) takes minified or messy JSON and re-emits it with consistent indentation, newline placement, and whitespace — making it readable by humans without changing the underlying data.

A JSON validator performs a stricter job: it parses the input according to the JSON grammar and reports whether it is well-formed. Validation is critical when debugging API responses, fixture files, or generated payloads, because a single missing comma or trailing bracket can break an entire pipeline. This tool performs both operations using Prettier, the same code formatter used by millions of JavaScript projects, so the output matches what you would get from running prettier --parser json locally.

A minifier does the opposite of a formatter: it removes every byte of non-semantic whitespace to produce the smallest possible valid JSON string. This is valuable for shipping smaller payloads over the wire — a minified JSON document can be 30–60% smaller than its pretty-printed counterpart, which directly reduces bandwidth costs and improves time-to-first-byte for API consumers.

No. This tool runs entirely in your browser. The Prettier library is bundled into the page, and the formatting work happens in your tab's JavaScript runtime. Your input never leaves your device, which makes this tool safe to use on confidential payloads such as production credentials, customer data, or signed JWTs.

Strict RFC 8259 JSON: objects, arrays, strings (with escape sequences), numbers, booleans, and null. JSONC (JSON with comments), JSON5, and TypeScript-style trailing commas are not supported by this particular tool. If you need JSONC formatting, use the JavaScript Formatter with the json parser override.

Yes, up to the memory limits of your browser. Files of a few megabytes format in well under a second. For files larger than ~50 MB you may notice UI jank; we recommend splitting the file or using a streaming parser such as stream-json on Node.js for those cases.

After the first visit, the page and its bundled Prettier library are cached by the browser. As long as the cache is intact, the tool will continue to work without a network connection.