jsonfmt.dev – Client-side JSON formatting, validation, conversion, and diff tool

Summary: jsonfmt.dev is a browser-based tool for formatting, validating, minifying, and converting JSON without sending data to a server. It supports tree view, diff, JWT decoding, and conversion to YAML, CSV, XML, TOML, Python, and Go formats, all offline and free to use.

What it does

jsonfmt.dev provides multiple JSON utilities including formatting, validation, diffing, conversion, JWT decoding, repair of common syntax errors, schema validation, JSONPath evaluation, and JSONL viewing. It operates entirely client-side as a single HTML file with no external dependencies.

Who it's for

It is designed for developers and users who need a fast, offline-capable JSON toolset without account requirements or data transmission.

Why it matters

It solves issues with existing JSON tools by offering a lightweight, privacy-focused, and comprehensive solution that works offline and does not require internet access or backend services.