.NET microservices architecture Tech Stack

A professional .NET microservices architecture along with justifications. I'll also include additional considerations where necessary.

1. Authentication

Best Choice: OIDC (OpenID Connect)
Justification: OIDC is built on top of OAuth2 and provides identity verification along with authorization. It is the industry standard for securing APIs and supports SSO (Single Sign-On) across microservices. OAuth2 alone lacks an identity layer, while Basic Authentication is insecure and unsuitable for modern microservices.

👉 Additional Consideration: Use IdentityServer, Auth0, or Azure AD B2C as an OIDC provider.

2. API Gateway

Best Choice: YARP
Justification: YARP (Yet Another Reverse Proxy) is a high-performance, modern, and extensible API Gateway designed for .NET. It supports dynamic route updates, better integration with Kubernetes, and lower overhead compared to Ocelot.

👉 When to Use Ocelot?
Ocelot is a good choice for simpler scenarios but lacks performance optimization for large-scale systems.

3. Database Strategy

Best Choice: Per Service Database
Justification: Each microservice should have its own database to ensure loose coupling, scalability, and data ownership. A shared database contradicts the microservices principle and creates a single point of failure.

4. Database Provider

Best Choice: MS SQL & PostgreSQL
Justification:

• MS SQL – Best for enterprise-level systems with strong ACID compliance.
• PostgreSQL – Open-source, excellent for scalability and JSON support (can replace NoSQL in some cases).
• MongoDB – Only for services needing high flexibility, schema-less storage, or event sourcing.

👉 Recommendation: Allow multiple providers based on service needs.

5. ORM

Best Choice: Entity Framework Core (EF Core)

• Justification: EF Core provides ease of use, code-first approach, and multi-database support. For high-performance scenarios, Dapper can be used as a complement.

👉 Additional Consideration: Use Dapper for read-heavy microservices.

6. API Type

Best Choice: REST (Primary) & GraphQL (Selective)
Justification:

• REST – Standard, well-supported, and easier for public APIs.
• GraphQL – Useful for complex queries and reducing over-fetching in micr oservices.

👉 Recommendation: Use GraphQL selectively for services requiring flexible data fetching.

7. API Documentation

Best Choice: OpenAPI (Swagger)
Justification: OpenAPI is widely adopted, automatically generated, and integrates well with .NET and API Gateway.

👉 Scalar is optional unless you're using GraphQL.

8. Coding Practices

Best Choice: Clean Architecture + MediatR + Repository Pattern

Justification:

• Clean Architecture – Ensures separation of concerns and testability.
• MediatR – Helps in CQRS, reducing dependencies, and improving maintainability.
• Reposi tory Pattern – Abstracts the database layer.

👉 Alternative: Consider Vertical Slice Architecture for better microservices modularity.

9. Testing Strategy

Best Choice:
Unit Testing → NUnit (more flexible than MSTest)
BDD → SpecFlow (for behavior-driven development)
Performance Testing → JMeter

10. Inter-Service Communication

Best Choice: Combination of REST, Message Queue, and gRPC
Justification:

• REST → For standard synchronous service calls.
• Message Queue (Kafka / RabbitMQ) → For event-driven architecture and decoupling services.
• gRPC → For high-performance inter-service communication, especially interna l services.

👉 Recommendation: Use Kafka for event-driven systems and RabbitMQ for task queues.

11. Scheduled Services

Best Choice: Hangfire + MongoDB

Justification:

• Hangfire is great for background job processing.
• MongoDB s tores Hangfire jobs efficiently without requiring SQL.

12. Caching

Best Choice: Redis
Justification:

• Redis is fast, scalable, and supports distributed caching.
• Mong oDB caching is less efficient compared to Redis.

13. Logging

Best Choice: Serilog
Justification:

• Serilog is structured logging, supports Elasticsearch, and integrates well with .NET microservices.
• NLog an d log4net are alternatives but less popular for modern architectures.

👉 Recommendation: Use Serilog + Elastic Stack (ELK) or Seq for centralized logging.

14. Service Monitoring

Best Choice: OpenTelemetry + Jaeger + Basic Health Monitoring
Justification:

• OpenTelemetry – Standardized tracing and metrics collection.
• Jaeger – Best for distributed tracing.
• Basic Health Monitoring – Use .NET HealthChecks for simple readiness and liveness probes.

15. CI/CD

Best Choice: Docker & Kubernetes
Justification: Kubernetes allows auto-scaling, self-healing, and efficient microservice deployment. Docker ensures consistency across environments.

👉 Additional Consideration: Use Helm charts for managing Kubernetes deployments.

16. Retry Policy

Best Choice: Polly
Justification: Polly provides resilience for microservices with features like:

• Retry policy
• Circuit breaker
• Bulkhead isolation
• Timeo ut handling

👉 Recommendation: Implement Polly middleware in API Gateway and microservices.

17. Secrets Management

Why? Avoid hardcoding sensitive information (DB credentials, API keys).
Tools:

• Azure Key Vault (if using Azure)
• AWS Secrets Manager (if using AWS)
• Vau lt by HashiCorp (for self-hosted solutions)

Final Notes:
This architecture ensures scalability, resilience, and maintainability.
Adopt best practices like CQRS, Domain-Driven Design (DDD) for complex domains.

Security: Ensure API Gateway handles authentication & authorization centrally.

Observability: Implement structured logging & monitoring to diagnose issues efficiently.