Microservice Architecture is a design pattern for building distributed systems where the application is split into small, independent services that communicate over a network—usually via HTTP/REST, gRPC, or messaging queues.
Core Concepts
1. Services are Independent
Each microservice:
- Has its own codebase
- Can be deployed independently
- Encapsulates a specific business capability (e.g.,
User Service,Order Service,Payment Service)
2. Decentralized Data
- Each service owns its data (no shared database).
- Promotes data autonomy and better scalability.
- Prevents tight coupling at the DB layer.
3. Inter-Service Communication
4. Service Discovery
Services need to find and talk to each other dynamically. Solved using:
- Registries (e.g., Consul, Eureka)
- DNS-based discovery (e.g., in Kubernetes)
5. API Gateway
- Acts as a single entry point.
- Handles routing, authentication, rate limiting, logging
- Popular options: Kong, NGINX, AWS API Gateway
6. Failure Isolation
- shouldn’t take down the whole system.
- Use circuit breakers, bulkheads, and timeouts.
Benefits
| Benefit | Description |
|---|---|
| Scalability | Scale services independently based on demand. |
| Flexibility in Tech Stack | Use different languages/tools for different services. |
| Faster Deployment | Services can be updated independently. |
| Fault Isolation | Failures are contained, not catastrophic. |
| Better Organization | Teams own specific services end-to-end. |
Challenges
| Challenge | Solution or Tool |
|---|---|
| Complex Deployment | CI/CD pipelines, Kubernetes |
| Service Coordination | Orchestration tools, Saga Pattern |
| Data Consistency | Eventual consistency, CDC, Idempotent ops |
| Observability | Logging (ELK), Monitoring (Prometheus), Tracing (Jaeger) |
| Testing | Contract testing, integration tests |
| Security | mTLS, JWT, service meshes (e.g., Istio) |
Key Patterns
- API Gateway Pattern – Central access point
- Database per service
- Service Registry & Discovery
- Saga Pattern – For distributed transactions
- Circuit Breaker Pattern – For resilience
When to Use Microservices
Use when:
- You have multiple teams, each managing separate parts of the system.
- The system needs to scale components differently.
- You expect frequent changes to parts of the system.
- You’re facing monolith scaling pain (build time, deploy time, team coordination).
Don’t use if:
- You’re a small team or early-stage startup (overhead > benefit).
- Your system isn’t complex enough to warrant splitting.
Typical Microservices Stack
| Layer | Common Tools |
|---|---|
| API Gateway | Kong, NGINX, AWS API Gateway |
| Service Comm. | REST, gRPC, Kafka |
| Service Reg. | Consul, Eureka, Zookeeper |
| Deployment | Docker, Kubernetes |
| Monitoring | Prometheus, Grafana |
| Tracing | Jaeger, Zipkin |
| Logging | ELK Stack, Loki |