JSON Formatter & Validator
Pretty-print, minify, or compact JSON and catch syntax errors instantly.
The JSON Formatter turns messy, minified, or broken JSON into something you can actually read. Paste any JSON document and it pretty-prints it with consistent indentation, makes it compact again when you need a small payload, and validates the structure as you type. If the document is not valid JSON, the tool points at the exact character and line where the problem is, which is the fastest way to fix trailing commas, missing quotes, or unescaped characters. It is especially useful when debugging API responses, inspecting config files, or shrinking JSON before you ship it. Everything runs locally in your browser, so sensitive payloads never leave your device. When the output is long, the consistent indentation and depth make it far easier to find the field you are looking for than in a single-line document. Pair it with the related guide on working with structured data for a fuller walkthrough. In day to day use the tool pays for itself the moment you are staring at a single line of JSON that a service returned and you need to find one field inside it. Pretty printing puts every object and array on its own indented level, so you can collapse the shape in your head and follow a path from the root to the value you want. The compact mode is the reverse direction and matters when the payload is going back over the wire or into a test fixture, because the extra whitespace is pure overhead. Validation is the third job and the one people underrate: a formatter that refuses invalid input and points at the offending character saves you from shipping a config that will only fail at runtime. A sane workflow is to paste the response, fix whatever the error points at, then copy the clean result back into your request or test so the two stay in step. Because formatting is a pure transform the document is never modified in place, which means you can keep the original and the formatted version side by side while you reason about the structure, and you never have to worry that a round trip through the tool silently changed a value.
Formatted JSON appears here.
Frequently Asked Questions
Why does my JSON fail to format?
Almost always a syntax error: a trailing comma, unquoted key, or single quotes. The formatter reports the location so you can fix it before parsing.
Should I minify or pretty-print in production?
Minify for transfer size; pretty-print for logs and debugging. The formatter switches between both without changing the data.
Is my data uploaded when I format it?
No. Formatting runs entirely in your browser; the JSON never leaves your device.