DDD-Driven B2C Platform: External Booking Center Integration

Project Context

The project consisted of building a B2C e-commerce platform on top of Magento 2 for a travel agency, where the commercial offering (hotels, cars, services) was managed externally by a specialized Booking Center. Magento was not the source of truth for products or availability. Instead, it acted as a commerce orchestrator, responsible for user interaction, checkout, and order lifecycle, while all booking intelligence lived outside the platform. The challenge was to integrate both worlds seamlessly without forcing Magento into a role it was not designed for.

Technical Challenge

The core difficulty was reconciling two fundamentally different models: Magento's catalog-driven commerce model and a real-time, API-driven booking system.

Key challenges included:

• • No physical products stored in Magento
• • Dynamic availability and pricing based on dates, number of travelers, and pickup locations
• • Real-time product discovery in PLP
• • Late-binding of offer details at PDP and checkout
• • Synchronization of Magento orders with the Booking Center lifecycle

A naive integration would have resulted in a fragile, tightly coupled system.

Architectural Solution

The solution was designed using Domain-Driven Design and Hexagonal Architecture, clearly separating responsibilities and bounded contexts.

• • Bounded Contexts and Domain Separation: The system was split into distinct Bounded Contexts, each with its own responsibilities and APIs: Search & Discovery Context (responsible for PLP generation, products are not persisted, results are built dynamically from Booking Center API responses), Offer Context (PDP resolves offer details in real time, final availability and pricing are validated just before add-to-cart), and Order & Booking Context (order lifecycle was explicitly modeled through independent Use Cases: Send Order to Booking Center, Cancel Booking, Close Booking and Invoice Generation).
• • Hexagonal Integration Model: The domain logic defines Ports representing interactions with the Booking Center (search offers, validate availability, create booking, cancel booking, close booking). Concrete Adapters implement these ports using the Booking Center API. This ensures no direct dependency from the domain to external APIs, replaceable or mockable integrations, and clear ownership of business rules.
• • Magento as an Application Layer: Magento was intentionally kept out of domain decision-making. Its responsibilities were limited to UI rendering, cart and checkout flow, order persistence, and event triggering. All business-critical decisions were delegated to the domain services exposed through the integration layer.

Testing & Quality Strategy

Quality and reliability were critical due to the financial and operational impact of bookings.

• • Domain isolation: Booking logic and order workflows were tested in isolation. External API interactions were mocked through adapter substitutions. No Magento bootstrap required for domain tests.
• • Contract testing: Strong contracts defined for Booking Center responses. Validation of edge cases: price changes, availability loss, partial booking failures.
• • Deterministic behavior: Each Use Case had explicit inputs and outputs. Result Pattern used to express success, recoverable errors, and business rule violations. This ensured predictable behavior across the entire booking lifecycle.

Results

Fully decoupled Magento from booking complexity, real-time product discovery without catalog persistence, clear and maintainable domain boundaries, robust order lifecycle synchronization with external systems, and a scalable architecture suitable for multiple sales channels.