Dotnet

Use TimeProvider instead of DateTime.UtcNow in testable code

Inject TimeProvider when business logic depends on the current time, then control that time in tests.

Validate required options at startup

Fail during application startup when required configuration is missing or invalid instead of waiting for the first request.

Use HybridCache for expensive AI work in .NET

Use HybridCache to avoid duplicate AI model calls, with a cached summarization example and deliberate cache-key design.

AsNoTracking belongs on read paths

Skip EF Core change tracking for queries that only read entity data, but keep tracking for load-change-save updates.

Use idempotency keys for retryable writes

Make a retried write replay the same operation instead of creating a duplicate side effect.

Generate Useful Test Data in .NET with Bogus

How to use the Bogus library to generate realistic, repeatable, and domain-shaped test data in .NET, including faker rules, related objects, seeds, and practical boundaries.

Use ValueTask only when you know why

Prefer Task unless you have a measured allocation reason and a simple consumption contract.

Keep agent tools narrow and boring

Expose only the small, specific capabilities the agent needs for the current workflow.

Make logs structured before adding dashboards

Capture queryable fields first so dashboards are built on data, not text search.

Use evals before changing prompts

Treat prompt changes like code changes: measure the behavior before deciding whether the edit helped.