Paste JSON to pretty-print it, validate it, or minify it. Syntax errors are pinpointed to the exact line and column, and the output is highlighted for easy reading.
Paste JSON below — it is validated as you type.
Pyalm builds custom software, APIs and integrations for businesses in India and the UAE. We made these developer tools for our own team — use them free, and talk to us when you need something built.
APIs, logs and config files often hand you JSON as one unreadable line. The formatter re-indents it with your choice of spaces or tabs, colours keys, strings, numbers and booleans differently, and can sort keys alphabetically so two payloads are easy to compare by eye.
A trailing comma, a single-quoted string or an unescaped newline is enough to break JSON. Instead of a vague 'invalid JSON', the validator reports the line and column of the first error and shows the offending line, so you can fix it in seconds.
📖 Read the full guide: How to Format and Validate JSON (and Fix the 6 Most Common Errors)
Compare two JSON documents and see every added, removed and changed value by path.
Decode a JSON Web Token's header and payload and read its claims and expiry.
Encode text to Base64 or decode it back — with full UTF-8 and URL-safe support.
Send GET, POST, PUT, PATCH and DELETE requests from your browser and inspect the response.
No. Parsing, formatting and highlighting all run in your browser with JavaScript's built-in JSON parser. Nothing you paste leaves the page, so it is safe for API responses that contain customer data or tokens.
Trailing commas after the last item, single quotes instead of double quotes, unquoted keys, comments (JSON does not allow them), and unescaped control characters inside strings. The validator points at the exact position of each.
Formatting adds indentation and line breaks so humans can read the structure. Minifying removes all unnecessary whitespace so the payload is as small as possible for transfer or storage. Both represent exactly the same data.
Several megabytes is fine in a modern browser. Very large files (tens of MB) still work but highlighting may take a moment; switch off highlighting for the fastest result.