api-design.md

technology	Microservices
domain	backend
level	Senior/Architect
version	Agnostic
tags	best-practices deterministic-code architecture-patterns vibe-coding microservices distributed-systems system-design solid-principles production-ready scalable-code
ai_role	Senior Microservices Architect
last_updated	2026-03-27

🧩 Microservices API Design

⬅️ Back to Parent

1. 🛑 Direct Service-to-Client Exposure

❌ Bad Practice

// Client talks directly to multiple microservices
fetch('http://user-service:3000/users');
fetch('http://order-service:4000/orders');

⚠️ Problem

Exposing individual microservices directly to clients creates security risks, forces the client to handle aggregation, and makes API versioning difficult.

✅ Best Practice

// Client talks to API Gateway
fetch('https://api.example.com/graphql');

Note

Internal Routing: For more context, refer back to the Microservices Index.

🚀 Solution

Implement an API Gateway or Backend-for-Frontend (BFF) pattern to act as a single entry point, handle cross-cutting concerns (auth, rate limiting), and aggregate responses.

2. 🗂️ Architectural Workflow

graph TD
    A[Client App] --> B[API Gateway]
    B --> C[User Service]
    B --> D[Order Service]

    classDef default fill:#e1f5fe,stroke:#03a9f4,stroke-width:2px,color:#000;
    classDef component fill:#e8f5e9,stroke:#4caf50,stroke-width:2px,color:#000;
    classDef layout fill:#f3e5f5,stroke:#9c27b0,stroke-width:2px,color:#000;

    class A layout;
    class B component;
    class C component;
    class D component;

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