Free online JSON tools
A small collection of JSON utilities for developers, tech writers, and anyone working with APIs. Everything runs locally in your browser, so you can safely paste production data without worrying about where it ends up.
1 tool available
Why use these json tools?
Safe for production data
Because JSON never leaves your browser, you can paste API responses, config files, or payloads that might contain secrets without risking exposure to a third-party service.
Instant feedback
No network round-trip. Paste JSON, click Prettify, see the result. Invalid JSON gets a clear error message with the parse position.
No clutter
No ads stuffed inside the textarea. No paywalls, no feature gates, no "sign up to continue." Just a textarea and a handful of buttons that do what they say.
Common use cases
- Formatting an API response pasted from curl or a browser network tab
- Minifying a config file before embedding it in a URL or environment variable
- Quickly checking whether a string is valid JSON before using it
- Cleaning up LLM-generated JSON that has inconsistent indentation
Frequently asked questions
Does this tool store my JSON anywhere?
No. All parsing and formatting happen in your browser using the built-in JSON parser. Nothing is uploaded or logged.
What are prettify, minify, and validate?
Prettify re-formats JSON with indentation so it is easy to read. Minify strips all whitespace to make the output as small as possible. Validate checks whether the input is well-formed JSON and reports any syntax error.
Can I format JSON that contains comments?
Strict JSON does not allow comments. If your input has them, remove or convert to a superset like JSON5 first — this tool uses the standard JSON parser.