Active Merchant VS Spree Commerce

For example, their theme templates use Liquid, which is a html templating system for Ruby. Activemerchant also was released by Shopify, and it provides a interface to major payment providers like PayPal.

For ruby there is a nice library from Shopify offering a huge number of payment gateway integrations: https://github.com/activemerchant/active_merchant

Administrate – for building and customizing admin panels; became successful because of its ease for users without a technical background. Money-Rails – for E-commerce solutions; enables creating monetary values, additional entry fields, and money classes. MetaTags – for SEO management, as the name suggests. Draper – for object-oriented programming; helps monitor and improve each object’s behavior. Dotenv – for safe loading environment variables to protect private data. ElasticSearch – to implement searches, to index catalogs and prices, to store purchases, and to gather statistics. Sidekiq – for storing, monitoring, and managing background jobs. Fog – for uploading and storing files via cloud services. Unicorn – for deploying. Active Merchant – for integrating payments.

A good system to study is Spree https://github.com/spree/spree. It has an inventory and billing system and supports different adjustments and sale configurations. If you don't want to use it wholesale it's a solid Rails application that does most of what you want so you can use it as solid inspiration.

Spree Commerce: https://spreecommerce.org/

Maybe Spree?

I'd say Solidus and Spree are you best options rather than trying to roll out you own ecommerce solution.

When I was working on that company, that mobile ordering app, Counterless, I looked a lot at codebases like Spree, the Spree Commerce codebase. And that's how I learned a lot about how do you model an order with line items and things like that? I saw some amazing things that helped me develop an understanding and save a ton of time by looking at oh, they have a state machine. What are the ways that an order transitions through all these different states as it gets processed and charged? And how do you track all of those things?