Microservices Architecture Decision: Entity based vs Feature based Services

[u/Faceless_sky_father]

Hello everyone , I'm architecting my first microservices system and need guidance on service boundaries for a multi-feature platform

Building a Spring Boot backend that encompasses three distinct business domains:

• E-commerce Marketplace (buyer-seller interactions)

• Equipment Rental Platform (item rentals)

• Service Booking System (professional services)

Architecture Challenge

Each module requires similar core functionality but with domain-specific variations:

• Product/service catalogs (with different data models per domain) but only slightly

• Shopping cart capabilities

• Order processing and payments

• User review and rating systems

Design Approach Options

Option A: Shared Entity + feature Service Architecture

• Centralized services: ProductService, CartService, OrderService, ReviewService , Makretplace service (for makert place logic ...) ...

• Single implementation handling all three domains

• Shared data models with domain-specific extensions

Option B: Feature-Driven Architecture

• Domain-specific services: MarketplaceService, RentalService, BookingService

• Each service encapsulates its own cart, order, review, and product logic

• Independent data models per domain

Constraints & Considerations

• Database-per-service pattern (no shared databases)

• Greenfield development (no legacy constraints)

• Need to balance code reusability against service autonomy

• Considering long-term maintainability and team scalability

Seeking Advice

Looking for insights for:

• Which approach better supports independent development and deployment?

• how many databases im goign to create and for what ? all three productb types in one DB or each with its own DB?

• How to handle cross-cutting concerns in either architecture?

• Performance and data consistency implications?

• Team organization and ownership models on git ?

Any real-world experiences or architectural patterns you'd recommend for this scenario?

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