🚀 Best Engineering Practices for .NET Core Development — Manager’s Playbook

1. Architect for Change, Not Just for Today

   Why: .NET Core evolves fast; your architecture must absorb change without rewrites.

   How to Implement

   • Use vertical slice architecture (feature folders) so each feature is self-contained.
   • Keep domain logic pure — no framework dependencies in core business rules.
   • Apply bounded contexts from DDD to avoid cross-module coupling.
   • Maintain Architecture Decision Records (ADRs) so future teams know why choices were made.

2. Performance as a First-Class Citizen

   Why: ASP.NET Core is fast, but careless patterns kill throughput.

   How to Implement

   • Make hot paths async end-to-end — no Task.Result or .Wait().
   • Use IAsyncEnumerable<T> for streaming large datasets instead of loading all into memory.
   • Profile regularly with dotnet-trace or PerfView to catch regressions early.
   • Cache aggressively (MemoryCache, Redis) but with expiry discipline to avoid stale data.

3. Security by Default

   Why: Security debt compounds faster than tech debt.

   How to Implement

   • Enforce HTTPS + HSTS in all environments.
   • Centralize claims-based authorization with policies, not scattered if checks.
   • Store secrets in Azure Key Vault or AWS Secrets Manager — never in config files.
   • Run OWASP ZAP scans in CI and fix findings before release.

4. Testing That Reflects Reality

   Why: Unit tests alone don’t protect production.

   How to Implement

   • Use WebApplicationFactory for API integration tests.
   • Spin up real dependencies in CI with Testcontainers (SQL Server, RabbitMQ, etc.).
   • Write scenario-based tests that mimic real user flows, not just method calls.
   • Track mutation testing scores to ensure tests actually catch bugs.

5. Observability as a Non-Negotiable

   Why: You can’t fix what you can’t see.

   How to Implement

   • Structured logging with Serilog + correlation IDs for every request.
   • Distributed tracing with OpenTelemetry to follow requests across services.
   • Health checks (Microsoft.Extensions.Diagnostics.HealthChecks) wired into monitoring dashboards.
   • Define SLOs (Service Level Objectives) and alert when breached.

6. Branching & Deployment Discipline

   Why: Release chaos kills velocity.

   How to Implement

   • Prefer trunk-based development with short-lived feature branches.
   • Every merge to main triggers build → test → security scan → deploy to staging.
   • Use blue-green or canary deployments for safe rollouts.
   • Keep rollback playbooks ready — including DB migration reversals.

7. Dependency & Package Hygiene

   Why: Outdated packages are a security and stability risk.

   How to Implement

   • Use central package management and NuGet lock files.
   • Audit dependencies quarterly; remove unused libraries.
   • Avoid “framework bloat” — only bring in libraries you truly need.

💡 Manager’s Tip

Don’t try to roll out all practices at once. Pick one technical, one process, and one cultural improvement per quarter. Measure impact, then iterate.