Solidus — Modular Open-Source E-Commerce Framework for Ruby on Rails

Introduction

Solidus is a full-featured e-commerce platform built as a set of Rails engines. Forked from Spree Commerce in 2015, it is maintained by a dedicated open-source community focused on stability, extensibility, and long-term support. Solidus provides everything needed to run an online store out of the box, while its modular architecture lets developers override, extend, or replace any component to fit custom business requirements.

What Solidus Does

• Manages products with variants, option types, properties, and inventory tracking
• Provides a multi-step checkout flow with customizable steps and guest checkout support
• Integrates with payment gateways including Stripe, Braintree, PayPal, and Adyen
• Handles shipping calculations with built-in calculators and support for custom shipping logic
• Includes a full admin dashboard for order management, customer records, and reporting

Architecture Overview

Solidus is composed of three Rails engines: solidus_core (models, business logic, and service objects), solidus_backend (admin interface), and solidus_api (RESTful JSON API). Each engine can be included independently. The framework uses a decorator and event system for customization, allowing developers to extend models, override views, and hook into lifecycle events without forking the source. A preferences system stores configuration in the database or in initializer files.

Self-Hosting & Configuration

• Add the solidus gem to an existing Rails application or start a new one
• Run the install generator to create database migrations, seed data, and initializer files
• Configure payment methods, shipping categories, and tax rates through the admin panel or initializers
• Customize the storefront by overriding views, adding Solidus extensions, or building a headless frontend via the API
• Deploy as a standard Rails application on any Ruby hosting platform (Heroku, Render, VPS, Kubernetes)

Key Features

• Fully open-source with no premium features behind a paywall
• Modular architecture with independently includable Rails engines
• Flexible product modeling with variants, option types, and configurable properties
• Extensible via community-maintained extensions for subscriptions, reviews, wishlists, and more
• Headless-ready with a complete RESTful API for decoupled frontends

Comparison with Similar Tools

• Spree Commerce — the original project Solidus forked from; Spree pivoted to a headless focus while Solidus maintains a full-stack approach
• Shopify — hosted e-commerce platform; easiest to start but proprietary with transaction fees and limited customization
• Saleor — Python/Django headless e-commerce with GraphQL API; modern stack but requires building the entire storefront
• Medusa — Node.js headless commerce engine; JavaScript-native but younger ecosystem
• WooCommerce — WordPress e-commerce plugin; massive ecosystem but tied to WordPress and PHP

FAQ

Q: What is the difference between Solidus and Spree? A: Solidus was forked from Spree in 2015 when the Spree team shifted focus to commercial products. Solidus remains fully open-source, community-governed, and focused on stability. The codebases have diverged significantly since the fork.

Q: Can Solidus be used as a headless backend? A: Yes. Solidus includes a RESTful JSON API and can be used as a headless backend with any frontend framework. The solidus_api engine can be included without the admin interface if needed.

Q: How does Solidus handle payments? A: Solidus uses a payment method abstraction that supports multiple gateways simultaneously. Official extensions provide integrations for Stripe, Braintree, PayPal, and Adyen. Custom payment methods can be added by implementing the gateway interface.

Q: Is Solidus suitable for high-traffic stores? A: Yes. Solidus runs on Rails and can be scaled horizontally with standard Rails deployment practices. Caching, background job processing, and database optimization follow standard Rails patterns.

Sources

• https://github.com/solidusio/solidus
• https://solidus.io/docs/