Solidus

Solidus is a Ruby on Rails‑based, open‑source e‑commerce framework that prioritizes extensibility and control. Built on Rails 7+, it leverages the full Rails ecosystem—ActiveRecord, ActionCable, and Hotwire—to deliver a modern storefront while keeping the underlying business logic modular. The platform exposes a REST‑ful API alongside GraphQL support, allowing developers to build headless storefronts or integrate with external services such as payment gateways, shipping providers, and ERP systems.

Architecture

• Language & Framework: Ruby 3.x + Rails 7.x, with a heavy emphasis on modular engines (e.g., solidus_core, solidus_backend, solidus_frontend). Each engine can be swapped or extended independently.
• Database: PostgreSQL is the default ORM backend, but any ActiveRecord‑compatible database can be used. Solidus ships with migrations that support schema versioning and data migration tooling.
• Background Jobs: Uses Sidekiq by default for asynchronous processing (order fulfillment, email notifications). Developers can replace it with Resque or DelayedJob if needed.
• Caching & Performance: Integrates with Redis for caching and session storage, enabling high‑throughput read/write operations. The API layer supports HTTP/2 and can be served behind a CDN for global latency reduction.
• Containerization: Dockerfiles are provided, and the community maintains Helm charts for Kubernetes deployments. The stack can be run in a single container or split into micro‑services (e.g., separating the API, admin UI, and background workers).

Core Capabilities

• Order & Inventory Management: Rich models for Order, LineItem, Variant, and StockLocation with built‑in state machines (state_machine) for order lifecycle.
• Payment Integration: Abstract Gateway interface supports Stripe, Braintree, Authorize.Net, and custom adapters. Webhooks can be configured to trigger order state changes.
• Shipping & Tax: Configurable shipping calculators (FlatRate, WeightBased) and tax engines that can be overridden with custom logic or external services (e.g., Avalara).
• API & Webhooks: RESTful endpoints for products, orders, customers, and inventory. Supports OAuth2 scopes for granular permission control. Webhook endpoints can be registered to receive real‑time events.
• Admin UI: Built with React (via solidus_admin) and Rails API, providing a responsive dashboard for product catalog, order management, analytics, and configuration.

Deployment & Infrastructure

Solidus is designed for self‑hosting, giving developers full control over data residency and compliance. Recommended infrastructure includes:

• Web Servers: Puma or Passenger behind Nginx/Apache.
• Background Workers: Sidekiq clusters with Redis persistence.
• Database Replication: PostgreSQL streaming replication for high availability.
• Scaling Strategy: Horizontal scaling of API workers and separate read replicas. The modular engine architecture allows gradual decoupling—e.g., moving the frontend to a separate Node.js service while keeping the core API intact.

Container images are available on Docker Hub (solidusio/solidus), and the project provides a docker-compose.yml for quick local setups. For production, Helm charts enable seamless deployment to Kubernetes with optional Istio service mesh integration.

Integration & Extensibility

• Plugin System: Solidus follows the Rails engine pattern; third‑party modules (e.g., solidus_payments, solidus_order_cycles) can be added via gems and mounted into the application. The community hosts a curated list of extensions on the Solidus website.
• API Hooks: Callbacks (after_create, before_update) and custom event handlers allow developers to inject business logic at critical points.
• Webhooks: Out‑of‑the‑box support for subscribing to events like order.completed or payment.failed. Handlers can be configured via the admin UI.
• Custom Themes: The frontend is built with Hotwire and Tailwind CSS, enabling developers to override templates or build completely custom storefronts while reusing the same backend logic.

Developer Experience

• Configuration: Centralized config/solidus.rb and environment‑specific YAML files let developers tweak everything from payment gateways to email delivery.
• Documentation: Comprehensive guides on the official Solidus website cover installation, customization, API usage, and best practices. The codebase is heavily commented, and the Rails engine structure follows standard conventions.
• Community & Support: Active Slack channel, GitHub Discussions, and an Open Collective fund. Regular releases (monthly) keep the stack up to date with Rails 7+ and Ruby 3.x.
• Testing: The project ships with RSpec, Capybara, and FactoryBot setups. Continuous integration runs on GitHub Actions, ensuring code quality before merges.

Use Cases

1. Enterprise B2C/B2B Stores – Companies needing a fully customizable checkout, complex inventory rules, and compliance with multiple tax jurisdictions.
2. Headless Commerce – Developers can expose the Solidus API and build a React/Vue/Flutter storefront, leveraging the same order logic.
3. Marketplace Platforms – The modular architecture allows adding vendor modules, commission calculations, and multi‑seller order flows. 4