Config & Protect: Configuration and Secrets Management in .NET

Managing configuration and protecting sensitive data is one of the most critical responsibilities of any .NET developer. Without proper handling of secrets and settings, even the most well-built applications are at risk of failure, misbehavior, or catastrophic security breaches. Config & Protect: Configuration and Secrets Management in .NET is your complete, hands-on guide to mastering configuration across development, deployment, and production environments using the tools built into the .NET ecosystem and beyond.
From local development with appsettings.json to production-grade secrets stored in Azure Key Vault, this book walks you through the essential practices and patterns every developer should know. Whether you’re building ASP.NET Core web applications, background services, microservices, or enterprise APIs, you'll learn how to structure, secure, and manage configuration settings with clarity and confidence.
You’ll start by understanding the core configuration system in .NET: how values are read, layered, and overridden using configuration providers such as JSON files, environment variables, and the command line. You'll explore how to use IConfiguration and bind configuration to strongly typed objects with the Options pattern, and how to validate critical settings before your app even starts.
Security is a top priority, and this book puts it front and center. You’ll learn how to manage secrets safely using environment variables and the .NET Secret Manager during development, and how to seamlessly integrate with secure secret stores like Azure Key Vault, AWS Secrets Manager, Google Secret Manager, and HashiCorp Vault in production environments. You’ll also discover how to handle secrets inside CI/CD pipelines without exposing them in logs, source control, or build artifacts.
Practical examples and real-world code are used throughout the book to demonstrate encryption, logging protection, and multi-environment deployments. You’ll learn how to encrypt sensitive data using the .NET Data Protection API, how to ensure secrets are not accidentally logged, and how to mock configuration for testing scenarios.
For enterprise teams and cloud-native applications, the book includes advanced strategies like per-tenant configuration, dynamic feature toggles, loading config from remote APIs, and setting up custom configuration providers. Every chapter is focused on making your applications more secure, maintainable, and reliable at scale.
Whether you're a junior developer working on internal tools, a senior engineer deploying global SaaS platforms, or a DevOps engineer managing secrets in automation pipelines, this book gives you the essential foundation for handling configuration and secrets the right way in .NET.
By the end of this book, you’ll be able to:

• Structure application configuration for any environment
• Use and validate appsettings.json, user secrets, and environment variables
• Securely access and rotate secrets from key vaults and external secret managers
• Avoid common pitfalls that expose secrets or create brittle apps
• Write testable, clean, and flexible configuration logic
• Apply configuration patterns in cloud-native, microservice, and enterprise applications

Config & Protect isn’t just a book about settings—it's a guide to building secure, flexible, and production-ready .NET applications. If you’re ready to take control of configuration and secrets in your .NET apps, this is the book that will get you there.