What is a JSON Formatter & Validator?
A JSON formatter pretty-prints compact JSON into an indented, readable structure — and a validator pinpoints exactly where malformed JSON breaks, instead of a vague parser error at the end of a log.
Paste anything from an API response to a config file. Parsing happens locally with your browser’s native JSON engine, so even large payloads with secrets never leave your machine.
The validator is the quiet hero: APIs, config files and log pipelines fail on a single missing comma, and the error engines report ('Unexpected token at position 4823') is useless in a one-line blob. Formatting first, then reading the exact line and column of the failure, turns a ten-minute hunt into a five-second fix.
How to use the JSON Formatter & Validator
- Paste JSON into the input.
- Press Format for indented output, or Minify for a compact single line.
- If the JSON is invalid, the error message shows the line and column to fix.
Frequently asked questions
Why does my valid-looking JSON fail?
The usual suspects: trailing commas (allowed in JavaScript, illegal in JSON), single quotes instead of double, and unquoted keys. The validator points at the exact position of the first violation.
What indent size does the formatter use?
Two spaces — the dominant convention in web tooling. Minify reverses it to a single line for env vars and payloads.
Is my JSON sent to a server?
No — formatting and validation use the browser’s built-in parser. Payloads with tokens or customer data stay on your machine.
What does the validator actually check?
Strict JSON syntax (RFC 8259): quoting, commas, brackets and value types. It does not check against a schema.
Can it handle large files?
Yes — multi-megabyte JSON formats fine; the limit is your browser’s memory.
Why minify JSON?
Minified JSON strips whitespace to cut payload size — useful for embedding in configs, env vars or HTTP requests.