JSON Formatter & Validator
Format, beautify, minify and validate JSON instantly.
JSON Formatter & Validator — Paste JSON to pretty-print it with 2-space, 4-space or tab indentation, or minify it for production. Errors are validated as you type and reported with the exact line and column. Your data is parsed entirely in the browser and never uploaded.
What is JSON Formatter & Validator?
A free online JSON formatter, beautifier, and validator that runs entirely in your browser. Paste minified or messy JSON and it pretty-prints the structure with your choice of 2-space, 4-space, or tab indentation, or switch to Minify mode to strip whitespace into one compact line for production. As you type it validates the syntax, and a Status readout shows Valid JSON or flags the first error, with its line and column appended when available. Backend and frontend developers use it to read and debug API responses, clean up config files, and verify payloads before committing them.
How to use JSON Formatter & Validator
- Paste or type your JSON into the Input box.
- Leave the mode on Format to beautify, or click Minify to compact everything onto a single line.
- Choose your indentation: 2 spaces, 4 spaces, or Tab.
- Check the Status panel - it reads Valid JSON, or shows Invalid with the line and column of the first error when a position is available.
- Use the Copy button to grab the formatted output, or click Clear to empty the input and start over.
Examples
Beautify a one-line object (2 spaces)
Input
{"name":"Ada","age":30}Output
{
"name": "Ada",
"age": 30
}Minify a config for production
Input
{
"debug": false,
"port": 8080
}Output
{"debug":false,"port":8080}Catch a trailing-comma error
Paste {"a": 1,} and the Status switches to Invalid, flagging the first syntax problem (such as a missing or extra comma, or a property name that needs quoting) with its line and column when a position is reported, so you can fix that spot.
Frequently asked questions
- Is my JSON uploaded to a server?
- No. Parsing, formatting, minifying, and validation all happen locally in your browser using the built-in JSON engine. Your data never leaves your device, and the tool keeps working offline.
- What indentation options can I use?
- In Format mode you can pretty-print with 2 spaces, 4 spaces, or a Tab character. Minify mode ignores indentation and removes all unneeded whitespace to produce a single line.
- Why does it say my JSON is Invalid?
- The validator reports the first syntax problem and, when the engine provides a position, appends its line and column. Common causes are a trailing or missing comma, an unclosed string or bracket, an invalid escape character, or property names that aren't wrapped in double quotes.
- Does it re-validate automatically?
- Yes. Validation and formatting update as you type, so the moment you fix the flagged spot the Status flips back to Valid JSON and the output refreshes instantly.
- Can it handle large JSON files?
- Yes. Because everything runs locally there's no upload wait, though extremely large inputs ultimately depend on your device's available memory.
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