JetBrains .NET Day Online 2026: Watch the Recordings

Every session from October 7 is now on YouTube.

.NET Day Online 2026 took place on October 7. Thanks to everyone who watched the livestream and asked questions in the chat! If you missed a session, or want to watch one again, all of them are now online.

Watch the full playlist

Here’s a quick overview of each session to help you decide what to watch.

Keynote: JetBrains .NET Tools in the Age of Agents

Anastasia Kazakova, Matt Ellis, Matthias Koch, and Mehul Harry

Anastasia opened the day by exploring how agents are changing what developers need from their tools and introducing JetBrains Air. Matt followed with a demo of Air in Rider. He gave Codex a task in a sample app, checked the result with Rider’s tests, navigation, and debugger, and left a review note that sent the agent back for another pass. He also showed how Rider shares its own tools with agents, through bundled skills for debugging and refactoring, and hooks that inspect and reformat the code an agent writes.

Matthias gave an agent the dottrace-analyze skill to investigate a slow app. The skill lets the agent read real profiling data and trace the hot paths back to the code, and in our evaluation, it raised the agent’s average accuracy from 4.7 to 8.1 out of 10. See the details in this blog post.

Mehul wrapped things up by discussing options for .NET developers to use ReSharper in VS Code and Cursor for those who work outside Rider.

Air is available as a plugin for Rider 2026.2 and is bundled with Rider starting with the 2026.3 EAP. You can also try Junie Lite, a free version of Junie, right from the Air model picker. Learn more at jetbrains.com/air.

Watch the keynote

Messaging Patterns for Modern Software Solutions

Irina Dominte

Irina walked through the Outbox, Inbox, and Saga patterns for distributed .NET systems, covering where each one helps and what it costs you to run.

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C# Interceptors: Native AOT and Performance for Free

Stefan Pölz

Stefan showed how C# interceptors and incremental source generators can replace reflection-based call sites. The payoff is code that trims better and works with Native AOT.

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Refinement-First Processes for AI Development

Stacy Cashmore

Stacy shared the process her team uses for AI development. They go from the problem to user stories before anyone writes code, then hand the build to specialized agents. She also took on lines of code as a measure of AI productivity and argued that the point is to solve user problems better.

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Building a Supply Chain Attack With .NET and NuGet

Maarten Balliauw

npm keeps facing supply chain attacks, and Maarten showed that .NET already has similar vulnerabilities. He demonstrated several ways to inject code through .NET, NuGet, and MSBuild, then covered how to reduce the risk.

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Modular Monoliths: The Goldilocks Architecture?

Steve Smith and Eric Fleming

Monoliths can turn into a big ball of mud, and microservices can turn into a distributed monolith. Steve and Eric made the case for a middle path, the modular monolith. It keeps deployment and hosting simple and still leaves room for several teams to work in one codebase.

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Interoperability of .NET

Sam Basu and Andres Pineda

Sam and Andres showed how far one .NET codebase can reach across mobile, desktop, web, and devices. They also built MCP servers with the C# MCP SDK.

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Introducing the SQL MCP Server

Jerry Nixon

Jerry introduced SQL MCP Server, Microsoft’s open-source MCP server for SQL Server, Azure SQL, PostgreSQL, Cosmos DB, and MySQL. He showed how it works alongside Data API builder, so language models can work with company data while permissions and policies control what they can access.

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Escape the Monolith: Scaling Blazor With .NET Aspire and Azure Container Apps

Michael Washington

Michael walked through Blazor Data Orchestrator, an open-source tool he created with a friend to schedule and run jobs in containers. Built with .NET Aspire and Blazor, it adds what they kept missing: a dashboard, centralized logs, and a way to package jobs and move them between environments. He also talked about how AI helped the two people build it on weekends.

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Thank you

A big thank you to all ten speakers for their time and talks. Thanks also to our hosts Matt Ellis, Rachel Appel, Matthias Koch, Michael Hawker, and Isaac Levin, and to everyone behind the scenes who kept the livestream running. This event is supported by the .NET Foundation.