Architecture Overview

platformkit is a modular monolith framework for building SaaS applications using a LEGO-block approach. Every component is composable, reusable, and industry-agnostic.

Core Layers

┌─────────────────────────────────────────────┐
│  Platform Layer (complete-saas)              │
│  Your application: config + module selection │
├─────────────────────────────────────────────┤
│  Module Layer (platform-modules)             │
│  30+ business modules: auth, billing, etc.   │
├─────────────────────────────────────────────┤
│  Framework Layer (backend/kit)               │
│  CRUD, entities, API, security, observability│
├─────────────────────────────────────────────┤
│  Infrastructure Layer                        │
│  PostgreSQL, Redis, NATS, Docker             │
└─────────────────────────────────────────────┘

Key Design Principles

1. Interface-First Design

Every capability is defined as an interface before implementation. Cross-module communication happens through ports — never by importing another module directly.

// ports/user.go — cross-module contract
type UserService interface {
    GetUser(ctx context.Context, id string) (*UserInfo, error)
}

2. Generic CRUD Services

Eliminate boilerplate with automatic API generation. Define an entity, get REST + MCP + admin UI for free:

type Product struct {
    base.BaseEntity[Product] `gorm:"embedded"`
    Name  string `gorm:"type:varchar(255)" json:"name"`
    Price int    `gorm:"not null" json:"price"`
}

3. Module Composition

Modules are selected at startup via a builder pattern:

modules := platformmodules.NewModuleSet().
    WithCoreVertical().
    WithShopManagement().
    WithContentManagement()

4. Event-Driven Architecture

Modules communicate asynchronously through NATS events:

eventBus.Publish(ctx, event.NewEvent(
    "order.created", orderID, "shop_management",
    map[string]any{"total": 99.99},
))

Directory Structure

What Makes It Different?

• True modularity: add or remove any module without breaking others
• Zero boilerplate: one entity definition → full API + admin UI
• AI-native: MCP integration makes every entity discoverable by LLMs
• Self-hosting first: single docker compose up deployment