Midas

Unified multi-currency monetary management for Rails

Overview

Midas centralizes all monetary behavior in Rails applications using a polymorphic Coin ledger.
Instead of duplicating price_cents and currency columns across dozens of models, Midas stores every monetary value in a single, consistent system.

This prevents rounding bugs, supports multi-currency conversion, and ensures financial logic remains predictable as your application grows.

Why Midas Exists

As systems scale, currency logic becomes one of the most fragile parts of an application.
Teams often duplicate conversion, rounding, and formatting logic in dozens of places.

Midas eliminates this entirely.

Key Features

Single polymorphic Coin model for all monetary values
Multi-currency support using the money gem
Declarative has_coin and has_coins DSL
Automatic conversion for integers, floats, and Money objects
Headless Stimulus-powered currency input field
Zero schema duplication
90%+ test coverage
Full API documentation and architecture overview

Documentation

Full documentation is available at:

https://midas.whittakertech.com

Installation

gem "whittaker_tech-midas"

Run migrations:

bin/rails railties:install:migrations FROM=whittaker_tech_midas
bin/rails db:migrate

Roadmap

Exchange rate fetching
Versioned coin histories
ViewComponent integrations
Billing integration examples (Stripe and LemonSqueezy)