About JSONLab

JSONLab is a free, privacy-first online workbench for working with JSON. It brings a complete set of tools together in one clean, ad-free interface — a JSON viewer, formatter, validator, diff checker and converter — so you can read, edit, debug and transform JSON without installing anything.

Our mission

We built JSONLab because developers deserve fast, reliable JSON tools that respect their data. Many online JSON utilities upload your payload to a remote server, wrap the page in ads, or hide useful features behind a sign-up. JSONLab takes the opposite approach: every feature runs locally in your browser, the interface stays clean, and everything is free to use.

Privacy by design

JSONLab processes your data entirely on your device. Your JSON is never uploaded to a server, which means sensitive API responses, configuration files and logs never leave your machine. The app even keeps working with no network connection at all. You can read more in our Privacy Policy.

What you can do with JSONLab

View & edit — explore JSON in a collapsible tree, add or rename keys, and copy the path to any value.
Format & minify — beautify JSON with 2-space, 4-space or tab indentation, or strip whitespace for compact output.
Validate & fix — catch syntax errors in real time and auto-repair common mistakes like trailing commas and single quotes.
Diff & merge — semantically compare two documents, merge changes and export RFC 6902 patches.
Convert — turn JSON into CSV, YAML, XML, TOML, and typed code for TypeScript, Java, Go, Python and Dart.
Query — filter and extract data with JSONPath and JMESPath.

Built for performance

JSONLab offloads heavy work such as parsing and comparison to background web workers, so the interface stays responsive even with large files (20MB+) that would freeze many other online viewers.

Get in touch

Have feedback, found a bug, or want to request a feature? We would love to hear from you — head over to our Contact page.