Building Distributed Applications that Work: Design, debug, test, observe, secure, and deploy

“Connects the developer experience to the real problems of distributed applications: configuration, dependencies, debugging, testing, and deployment.”
—Scott Hanselman, Microsoft

Systems that are split into independent, network-connected services, whatever their benefits, can be difficult to design, deploy, and maintain. In Building Distributed Applications that Work, author Fiodar Sazanavetsshows you how to conquer the inevitable communication failures, complex startup dependencies, and fragmented diagnostic data using industry-grade architectural patterns. Written for busy builders and software shippers, this book sticks to the techniques you’ll actually need—all demonstrated with examples using the .NET Aspire framework. Practical from the very start, this book gives you the tools and techniques to have a real project up and running by the end of the first chapter!

Building Distributed Applications that Work introduces a realistic e-commerce application that provides a clear, step-by-step progression through essential cloud-native concepts. You’ll start by mastering local orchestration and service discovery to establish clean service boundaries. Then, you’ll make your system resilient and scalable by externalizing state into relational databases, document stores, and cloud-native blobs. This hands-on journey helps you learn how to handle real-world system evolution cleanly rather than studying isolated code snippets or simplified, abstract configurations.

As your distributed system grows, you’ll add other elements from the Aspire ecosystem, including interactive SignalR tracking and local AI capabilities. Reviewer Rob Ruetschof Little Bird GmbH praised the “forward-leaning” examples, commenting, “Very realistic. I love that MCP and agents were discussed in chapter 10!” You will host local language models using Ollama and build autonomous, tool-calling AI agents. This modern approach to intelligent systems ensures you can safely build smart, responsive applications that are fully prepared for next-generation enterprise workloads.

Because graceful failure is mandatory for distributed systems, you’ll explore asynchronous message queues, distributed locking, and end-to-end token security. Reviewer David Sellenof Sweet Systems pointed out that “even for simple applications, visibility into logs, traces, and metrics is essential, and this book is a great introduction to observability!” By learning to construct robust integration tests, configure Open-Telemetry, and secure microservices via OIDC and JWT token propagation, you ensure your applications are resilient, highly observable, and production-ready. As you build your distributed application in Aspire, author Fiodar Sazanavetscarefully expands each concept so you can reproduce it in your framework of choice.

For .NET developers, this book is a practical guide to Aspire’s dashboard, AppHost, and service defaults. Developers and DevOps practitioners from other ecosystems will also gain transferable insight into orchestrating, observing, testing, and deploying multi-service applications—though the hands-on examples use .NET and Aspire.

What’s inside

• Code-first microservices orchestration
• OpenTelemetry distributed tracing and structured logging
• Securing cross-service communications with Keycloak, OIDC, and JWTs
• Deploying containerized workflows to Kubernetes and Azure
• Examples use the .NET Aspire framework

About the reader

This book is designed for mid-career software engineers, architects, and DevOps professionals seeking hands-on patterns to build, observe, and deploy resilient distributed systems.

About the author

Fiodar Sazanavetsis a senior software engineer, independent consultant, and Microsoft MVP. He has designed and scaled massive distributed systems, including high-throughput real-time data pipelines.

Table of Contents

Part 1
1 Getting started with distributed systems and Aspire
2 Managing infrastructure components with containers and integrations
3 Using database and storage components
Part 2
4 Adding order-tracking functionality with SignalR
5 Building a ChatGPT clone with Aspire, Ollama, and Semantic Kernel
Part 3
6 Integration testing and monitoring
7 Components for messaging and caching
8 Application security in Aspire
Part 4
9 Deploying Aspire apps to production
10 Adding legacy apps to Aspire and working with AI agents