.NET at Microsoft Build 2026: Must watch sessions

That’s a wrap on Microsoft Build 2026! From union types in C# to agentic web apps and AI on the edge with .NET MAUI, this year’s event showed how .NET 11 is built for the AI era. Whether you joined live or are catching up on demand, here are the .NET sessions worth your time.

Featured .NET Sessions

Union types in C#

Union types are coming to C#! Unions model closed sets of data shapes, as commonly seen in wire protocols and domain modeling. Mads and Dustin explore the clean expression of intent and the confidence and elegance that unions lend to consuming code. This is one of the most requested language features, and it’s finally landing.

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.NET 11 in depth: Runtime, libraries, and SDK for the AI era

.NET 11 delivers a new wave of improvements across the runtime, libraries, and SDK to help developers build modern applications for the AI era. This session takes an in-depth look at the key investments in performance, diagnostics, and developer productivity, and how they come together to support intelligent, cloud-connected, and agent-driven apps.

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AI Building Blocks for .NET: Add intelligence to your C# apps

A practical, opinionated guide to building intelligent apps in .NET. This session walks you through the building blocks you need to add AI capabilities to your C# applications, from model integration to agent patterns, all with production-ready code you can use today.

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Building for the agentic web with .NET 11

The demands on modern web apps are increasing. Users expect more performance, airtight security, and even agentic capabilities. In .NET 11, ASP.NET Core and Blazor are getting faster and more secure at the core, closely integrated with Aspire for distributed app development, and gaining a new set of building blocks (agents, tools, skills, and components) for building agentic web apps. Get ready to build for the modern agentic web!

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Taking your AI to the edge with .NET MAUI

AI is transforming both what we build and how we build it. Learn how .NET MAUI developers can bring AI to the edge using local models and on-device capabilities across mobile and desktop. This session covers the impact on privacy, performance, and UX, explores .NET 10 features and what’s coming in .NET 11, and shows how AI-powered tools and agentic workflows can accelerate app development.

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Simplifying .NET Installs with dotnetup

A new way to manage .NET SDK and Runtime installations that works for every user, on every platform! The dotnetup tool simplifies getting started with .NET and keeping your installations up to date, making the developer onboarding experience smoother than ever.

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Related Sessions

Looking for more? These related sessions from Build 2026 cover topics that intersect with .NET development.

Visual Studio

• GitHub Copilot in Visual Studio: Agents That Debug, Profile, and Test: Visual Studio goes beyond code generation with built-in agents that root-cause bugs using live runtime behavior, pinpoint performance bottlenecks, and build test coverage to catch regressions before they ship.

Aspire

• Aspire for agents: Transform how you build and deploy distributed apps: Aspire is now an open-source cloud and agent-ready developer toolchain transforming how you build, run, and deploy observable, production-ready distributed apps. Its code-centric approach streamlines orchestration of your apps and agents.

Windows development

• Building WinUI Apps with C# First Patterns and AI Assisted Workflows: See how emerging C# first patterns improve developer productivity in WinUI, how experimental work like Reactor informs future direction, and how these changes fit alongside the XAML-based apps you’re shipping today.

Microsoft Foundry

• From prototype to production build and run agents at scale: AI agents are transforming how developers build software, but shipping production-grade agents demands more. This session walks through the end-to-end lifecycle of building AI agents with Foundry Agent Service and Microsoft Agent Framework. See how to go from local prototyping to enterprise-grade hosted deployment with identity, secure networking, evaluations, and lifecycle management. Learn how coding agents like GitHub Copilot integrate directly into the workflow.
• Claw and agent harness in Microsoft Foundry: Go deep on multi-agent systems built on Microsoft Foundry, featuring Claw agent patterns and the hosted agents architecture. See how coding agents integrate into multi-agent workflows using Microsoft Agent Framework.

GitHub Copilot SDK

• Your agent, anywhere: MultiClient, MultiDevice with GitHub Copilot SDK: See how the GitHub Copilot SDK lets you build an agent, embed it in an app, and take it across devices and into the cloud. Go from a local agent to one you can access on your phone, move between machines, and run across multiple clients.

App modernization

• Modernize intelligent apps and agents with .NET that scale as you grow: Learn how to modernize legacy .NET apps without code rewrites using Managed Instance on Azure App Service, removing migration blockers while reducing cost and accelerating innovation.
• Using AI tools to teach old apps new tricks: See how agentic AI takes on the hardest parts of modernization: analyzing large codebases, mapping dependencies, planning upgrades, and refactoring safely at scale with GitHub Copilot.

📚 Get Started

Ready to dive in? Here’s how to get started with everything announced at Build 2026.

• Watch the .NET at Build 2026 playlist
• Download .NET 11 Preview
• Build 2026 Book of News
• .NET YouTube channel