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JSON Formatter & Validator
Format, validate and pretty-print JSON in your browser — no data leaves your machine.
What is a JSON formatter?
Paste minified or messy JSON and get a readable, indented version back — or find out exactly why it's invalid. Parsing happens entirely in your browser: nothing you paste here is sent anywhere.
Common uses
- Debugging an API response pasted from the browser Network tab or Postman
- Cleaning up minified JSON from logs or a config file
- Validating JSON before committing it to a config file
- Sanity-checking JSON you’re about to paste into code
FAQ
Does this validate against a JSON Schema?
No — it only checks that the JSON syntax itself is valid, not that it matches a particular schema.
Is there a size limit?
No hard limit, but very large payloads (several MB) may be slow since parsing runs on the main thread.
Does it support JSON5 or JSONC (comments, trailing commas)?
No — only standard JSON. Comments and trailing commas will show as invalid.