Ferrum

FerrumKit

Alpha

JSON, JWT, Base64, regex, hashes and timestamps in one native window. Nothing leaves your Mac.

The small tools you otherwise look up on random websites, in one native window. Everything runs on your Mac, so tokens and payloads never leave it.

Download LauncherInstall with Ferrum Launcher

What FerrumKit does

Every tool's logic is a plain Rust function covered by unit tests; the window is new in this alpha.

  • JSON, YAML and TOML

    Format, minify and validate JSON with the exact line and column of an error, and convert between JSON, YAML and TOML.

  • JWT decoder

    Header and payload pretty-printed, with exp, iat and nbf shown as dates and an expired warning. Decoding only: signatures aren't verified.

  • Encoders

    Base64 (standard and URL-safe), URL encode and decode, and a URL parser that lays out the query parameters as a table.

  • Generators

    UUID v4 and v7, ULID, and MD5, SHA-1, SHA-256 and SHA-512 hashes of any text.

  • Regex tester

    Matches highlighted as you type and capture groups listed, using Rust regex syntax.

  • Converters

    Unix timestamps and dates, number bases, colours (hex, RGB, HSL), text case, line tools and a text diff.

Status: Alpha

FerrumKit is in alpha. The tools are tested; the GPUI window is new and still being polished.

Works today

  • A searchable sidebar of tools, with ⌘K to search
  • JSON format, minify, validate and JSON ⇄ YAML ⇄ TOML
  • JWT decode, Base64, URL encode and parse
  • Timestamps, UUIDs and ULIDs, hashes
  • Regex tester, text diff, number base, colour and case converters
  • Copy buttons on every output

Not built yet

  • Saved inputs between launches
  • A global shortcut to open a tool from anywhere
  • JWT signature verification
  • Wrapping long lines (they scroll sideways) and arrow keys in the tool list

Requirements & built with

Install
Ferrum Launcher (free, see Download)
Network
None: every tool runs offline
Builds
macOS (Apple Silicon and Intel), Linux x86_64 and Windows
Built with
Rust, GPUI, serde, regex
Tested on
macOS

The JWT decoder shows what a token says; it doesn't prove who signed it.