JSON Formatter & Validator

Format, validate, and minify JSON in your browser

Paste raw JSON and get it back cleanly indented (beautified), or minified down to a single line. It validates as it goes: if the JSON is malformed, you get the specific parser error with the line and column where it broke, instead of a vague "invalid" message. Everything runs in your browser using the built-in JSON engine, so even large payloads never leave your device.

How to format JSON

1. Paste your JSON into the box above, or drop a .json file onto it.
2. Pick an indent — 2 spaces, 4 spaces, or tabs — and optionally tick Sort keys.
3. Click Format to beautify, Minify to collapse to one line, or Validate to just check it's well-formed.
4. Use Copy or Download to grab the result.

Format, minify, validate, or sort keys — when to use which

Format re-indents with two or four spaces, or tabs — whichever your codebase uses — so a minified or hand-mangled blob becomes readable. Minify strips every optional space and newline, which is what you want before embedding JSON in a URL, a config value, or a size-sensitive payload. Validate checks the syntax without changing anything. Sort keys reorders object keys alphabetically at every level, which makes two JSON blobs diff cleanly even if they were generated in a different order.

Why format JSON locally instead of on a website?

Many "JSON formatter" sites post whatever you paste to a server. That's usually harmless, but JSON often carries exactly the things you don't want to send anywhere: API keys, access tokens, customer records, internal identifiers, an entire API response. Doing it locally removes that risk entirely — there is no server to receive the data, which you can confirm in your browser's network tab, and it keeps working offline.

Large files won't freeze the tab

Formatting a multi-megabyte payload on the main thread can lock a browser tab for seconds. Above a size threshold this tool hands the work to a background Web Worker, so the page stays responsive while it runs — useful when you're pretty-printing a big API response or an exported data dump.