Developer Tool
Quickly format, validate, and analyze JSON. Get precise error locations for invalid JSON.
Paste JSON here…
A JSON formatter and validator takes JSON that's crammed onto one line and indents it so it's readable, and when there's a syntax error it points to the exact line and column that's wrong. Beyond pretty-printing, it can minify (strip whitespace to shrink the size), sort keys, show the structure as a collapsible tree, highlight syntax, and even load JSON from a web address (URL). All processing happens inside your own browser.
1. Paste JSON into the input on the left, or load it from the URL of a public API or .json file. 2. Choose the indentation style and whether to sort keys. 3. The formatted result appears on the right, and any error is reported with its location. Copy the result or download it as a file, or minify it into a single line.
Debugging an API response by expanding crammed JSON to see its structure, hunting down a typo or an unbalanced bracket in a config file (package.json, tsconfig, and the like), tidying JSON printed in a log, or sorting keys before sharing it with someone. It's also used to minify JSON down to reduce transfer size.
The error message gives a line and column — start there. The usual culprits are a missing comma, an unclosed quote or bracket, or a stray trailing comma after the last item. Loading from a URL needs the server to allow CORS; if it's blocked, just copy the content and paste it in. Sorting keys makes changes easier to compare (diff) in version control.
JSON (JavaScript Object Notation) is a text format for structured data. It's widely used in web APIs and configuration files.
Formatted JSON is easier to read, debug, and compare in version control.
Yes, all processing happens in your browser. Your JSON never leaves your device.
Yes, paste the URL of a public JSON API or .json file. The server must allow CORS.
It validates against standard JSON. Comments (//) and a comma after the last item aren't allowed in standard JSON and are flagged as errors, so stick to standard syntax.
It runs in your browser, so it depends on your device, but typical API responses and config files are handled with no trouble.