About JsonYaml-Formatter

A free, fast, privacy-first JSON and YAML formatter, validator and converter that runs entirely in your browser.

JsonYaml-Formatter exists to fix a small but constant annoyance for developers: needing to quickly format, validate, compare or convert a JSON or YAML document without installing anything, creating an account, or worrying about where the data ends up.

What we built

The tool combines a JSON formatter, a YAML formatter, a validator, a JSON <-> YAML converter and a side-by-side compare view in one page, powered by the Monaco editor (the same editor that powers VS Code). Everything -- parsing, formatting, validation, conversion and diffing -- happens in JavaScript inside your browser tab.

Why it's free and has no account

There is no backend, no database and no sign-up because there doesn't need to be one. The tool doesn't store or process your documents on a server, so there's nothing for an account to protect and no infrastructure cost tied to how much you use it. The only things saved locally are your own editor preferences (theme, indentation, layout), kept in your browser's local storage on your own device.

Who it's for

Developers debugging an API response, DevOps engineers sanity-checking a Kubernetes manifest, students learning JSON and YAML syntax, and anyone who just needs a document formatted correctly before it goes into a config file, a bug report, or a pull request.

Have a feature request, found a bug, or just want to say hello? Get in touch on the Contact page.

Ready to try it? Head back to the free online JSON and YAML formatter, validator and converter to format, validate, compare or convert your own document.