JSON Formatter & Validator Free — Beautify & Debug JSON
Real-time validation and high-fidelity formatting for professional data workflows.
Technical FAQ
Is my data safe?
What's the difference between Format and Minify?
Which JSON standards are supported?
The Six Errors Behind Almost Every 'Invalid JSON'
The six common JSON errors
JSON looks like JavaScript but is far stricter — and the difference is exactly where parsing fails. When the validator flags your input, it's nearly always one of these:
| Error | Broken | Valid JSON |
|---|---|---|
| Trailing comma | {"a": 1, "b": 2,} | {"a": 1, "b": 2} |
| Single quotes | {'name': 'Ali'} | {"name": "Ali"} |
| Unquoted keys | {name: "Ali"} | {"name": "Ali"} |
| Comments | {"a": 1} // count | JSON has no comment syntax — remove them |
| undefined / NaN | {"score": NaN} | Use null: {"score": null} |
| Smart quotes from copy-paste | “name”: “Ali” | Straight quotes only: "name": "Ali" |
Debugging an API response in 30 seconds
A minified API response is one endless line; the error message says “position 4,217” and nothing else. Paste it here, format, and the structure becomes readable with the error line visible in context. The tree view collapses nested objects so you can navigate a deep response without losing your place — handy for payment-gateway callbacks and bank API responses where the field you need sits five levels deep. Everything parses locally in your browser, so production payloads with tokens and customer data never leave your machine.
Format for humans, minify for machines
Pretty-printed JSON with 2-space indentation is for reading and code review; minified JSON is for shipping — whitespace can be a third of a large payload's size. Format while developing, minify what you deploy or store. Converting between formats is its own job: turn spreadsheet exports into API-ready data with CSV to JSON, flatten API responses for Excel with JSON to CSV, or translate Kubernetes and CI configs with YAML to JSON.