JSON Formatter

What this JSON formatter does

This English-language JSON formatter and validator gives you clean, readable output in one click. Paste raw or minified JSON — the formatter indents every nested object and array, checks the structure against RFC 7519-adjacent standards, and points to the exact line and column where a syntax error occurs. You can choose 2-space, 4-space, or tab indentation, or flip it around and minify a pretty-printed payload down to a single compact line. The IETF maintains over 9,500 RFCs, and JSON's own spec — RFC 8259 — defines strict rules that trip up even experienced developers: trailing commas, single-quoted strings, unquoted keys, and inline comments are all invalid in standard JSON even though they are legal in JSON5 or YAML. 100% client-side — your data never leaves your browser. No uploads, no tracking, no server logs. That makes it safe for production API responses, internal configs, and anything containing secrets or PII.

Features

• Instant beautifier. Reformats minified or hand-written JSON into indented, human-readable output. Works as a full JSON beautifier online with no size restrictions imposed by a server.
• Inline validator with error pointer. Strict RFC 8259 validation flags every syntax issue — trailing commas, unquoted keys, unescaped control characters — and reports the exact line and column so you can fix it fast.
• Configurable indentation. Switch between 2 spaces (JavaScript default), 4 spaces (Python's json.dumps style), or a hard tab to match your team's coding style guide before pasting into a PR.
• One-click minifier. Strips all whitespace to produce the most compact valid JSON — useful when you need to embed a payload in a curl command, a Postman environment variable, or a CI config.
• Privacy-first, fully offline-capable. All processing runs in your browser via native JavaScript — the same engine that powers JSON.stringify(JSON.parse(raw), null, 2). Nothing is sent to any server, so you can safely format internal API responses, secrets, or database exports.
• Cross-format awareness. Spotted a config that looks like JSON but uses YAML-style keys or comments? After fixing it here, you can pass the clean output through our [JSON ↔ YAML converter](/en/json-yaml-converter/) to switch formats without losing structure.

How to use the JSON formatter

Three steps from raw payload to clean, validated output — no account or install needed.

1. Paste your JSON. Copy any JSON string — an API response, a config file like package.json or tsconfig.json, or a log line — and paste it into the input area.
2. Choose your indent style. Select 2 spaces, 4 spaces, or Tab from the Indent control. 2 spaces matches the JavaScript convention (JSON.stringify(JSON.parse(raw), null, 2)); 4 spaces matches Python's json.dumps(json.loads(raw), indent=2).
3. Click Format or Minify. Hit Format to beautify. If the JSON is invalid, the error panel shows the exact line and column of the first syntax issue. Hit Minify to collapse everything to a single line instead.
4. Copy the result. Use the Copy button to put the formatted or minified output on your clipboard, ready to paste into your editor, terminal, or request body.

Common use cases

• Debugging API responses. When a REST endpoint returns a wall of minified text, pasting it here gives you an indented tree you can scan visually — useful for responses from payment APIs, maps services, or any JSON-heavy backend.
• Reviewing config files. Files like package.json, tsconfig.json, and ESLint configs need to be valid strict JSON (no comments, no trailing commas). The validator catches those mistakes before they break a CI pipeline in Chicago or San Francisco.
• Composing curl and Postman request bodies. Write a readable multi-line JSON body, validate it, then minify it into a single-line string you can drop into a -d flag or a Postman pre-request script without escaping issues.
• Reading structured logs. Log aggregators often emit compact JSON lines. Paste a single log entry to see every nested field clearly, then use the line/column pointer to investigate malformed entries that break your parser.
• Generating TypeScript interfaces. Once your JSON is clean and validated, feed it into our [Json To Typescript](/en/json-to-typescript/) tool to generate matching TypeScript interfaces automatically — no manual typing of field names.

Frequently asked questions