Built for developers, kept private
JSON FYI is a small toolbox for working with JSON: validate, lint, format, minify, and explore.
Most online JSON tools upload your data to a server. That's a privacy and compliance problem when you're debugging production payloads, inspecting API tokens, or parsing customer records.
JSON FYI is different: every byte stays in your browser. The parser, linter, formatter, and tree viewer are all written in TypeScript and run client-side. Once the page is loaded, you can disconnect from the network and keep working.
The validator follows RFC 8259 strictly. The linter adds warnings for the patterns that trip up newcomers (and seasoned engineers, honestly): trailing commas, duplicate keys, JavaScript comments, Python literals.
If you find a bug or have an idea, the project is intentionally minimal — open an issue and it'll likely ship the same week.