JSON Formatter & Validator

Paste any JSON and get instant formatting, validation, and minification. If your JSON is broken, the formatter pinpoints the exact line and character where the error is. It can even attempt to repair malformed JSON — missing quotes, trailing commas, truncated responses from an LLM, that kind of thing.

What it does

▸Beautifies JSON with configurable indent (2, 4, tab, or minified)
▸Validates and shows the exact line/character of syntax errors
▸Repairs broken JSON using a fault-tolerant parser (toggle the Repair option)
▸Sorts keys alphabetically, recursively through nested objects
▸Runs JSONPath queries against the parsed result to extract specific fields
▸Flags BigInt values that JavaScript would silently lose precision on

Use cases

▸Prettifying a minified API response so you can actually read it
▸Finding the syntax error in a hand-edited JSON config file
▸Repairing a truncated JSON response from an AI model or streaming endpoint
▸Extracting specific fields from a large nested payload with JSONPath

How it works

Paste or drop your JSON into the input pane

The formatter parses, validates, and beautifies it instantly

If there's a syntax error, you get the line number and character position

Toggle Repair mode to attempt fixing common JSON mistakes automatically

Frequently asked questions

1Can it handle large JSON files?

Yes. Parsing happens locally in the app, not on a server. Files up to several megabytes format instantly. The JSONPath query field lets you extract just the parts you need from large payloads.

2What does the Repair option do?

It uses jsonrepair, a fault-tolerant parser that fixes common issues: missing quotes around keys, trailing commas, single quotes instead of double, truncated input, and similar mistakes that break strict JSON.parse.

3Does it send my data anywhere?

No. Everything runs locally inside the app. Your JSON never leaves your machine, which matters if you're working with API keys, credentials, or sensitive payloads.