Fiodar Sazanavets

Building Distributed Applications that Work

"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 Sazanavets shows 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 Ruetsch of 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 Sellen of 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 Sazanavets carefully 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.

Building IoT Applications with SignalR

SignalR is an ASP.NET Core library that adds real-time web functionality to your apps, enabling server-side code to instantly communicate with your client. It’s an ideal library for facilitating the lightning-fast communication needed for a real-world Internet of Things project.

In this liveProject, you’ll put SignalR into action to build and implement an airport PA system across the Internet of Things. Your challenge will include creating both the server-side web application using ASP.NET Core with JavaScript front-end and the distributed application that will be deployed on the IoT devices on the ground using .NET Core and Docker. You’ll establish your SignalR setup, enable the transfer of real-time audio data, and enable your IoT applications to both run as a single cluster and deploy on Docker.