JSON FYI

JSON FYI is an in-browser tool for validating, formatting, minifying, linting, and exploring JSON documents. It addresses the need for quick syntax checking and structural inspection of JSON data without requiring external servers or accounts.

The tool performs instant validation as text is entered, reporting parse errors with exact line and column numbers along with hints and code snippets. It applies lint rules that detect trailing commas, duplicate keys, comments, and unquoted identifiers. Users can beautify output using 2-space, 4-space, or tab indentation, optionally sort keys, or minify content to a single line. A collapsible tree explorer displays nodes with type badges and allows copying JSONPath expressions such as $.users[0].email for any selected item.

JSON FYI operates entirely within the browser, processing all data locally with no uploads or logging. It supports drag-and-drop file loading, keyboard shortcuts for formatting and minification, undo, download, and sample documents. The interface shows summary statistics including node count, depth, and size. It remains functional offline after the initial load.

The service is provided free of charge with no signup required. It is designed for developers handling JSON data who require a private, client-side workflow.