You write tests - but are they valuable tests? Carl and Richard talk to Egil Hansen about his approach to creating tests for applications. Egil discusses the types of testing and who they impact. Testing isn't only for you! Valuable tests are also durable, being able to persist between changes where it makes sense, and help to understand when updates are going to create problems. The role of LLMs in generating code comes into play: should AI write your tests, evaluate them, or do both? Lots of great thinking from someone who's been helping developers build better tests for years!

AI in the cloud dominates, but what can you run locally? Carl and Richard speak with Joe Finney about his work in setting up local machine learning models. Joe discusses the non-LLM aspects of machine learning, including the vast array of models available at sites like Hugging Face. These models can help with image recognition, OCR, classifiers, and much more. Local LLMs are also a possibility, but the hardware requirements become more significant - a balance must be found between cost, security, and productivity!

How has AI changed coding with Visual Studio Code? Carl and Richard talk to James Montemagno about his experiences using the various LLM models available today with Visual Studio Code to build applications. James talks about the differences in approaches between Visual Studio and Visual Studio Code when it comes to AI tooling, and how those tools continue to evolve. The conversation also digs into how different people use AI tools to answer questions about errors, generate code, and manage projects. There's no one right way - you can experiment for yourself to get more done in less time!

Razor Tooling is evolving! Carl and Richard talk to David Wengier about the changes coming for Razor Pages in the next version of Visual Studio. David talks about the realization that much of the new work in Razor ties closely to Roslyn, which has resulted in a new co-hosting model that means higher performance and reliability for your web pages! The conversation delves into how capabilities in Visual Studio Code are shared with Visual Studio and vice versa, as well as the role of the Language Service Protocol in making it easier to bring more powerful tools to you.

Ready for the next version of Visual Studio? Carl and Richard talk to Mads Kristensen about the long-awaited version of Visual Studio. Needless to say, artificial intelligence sits front and center. Mads talks about the deep integration of AI across the development lifecycle, including code completion, debugging, even natural language querying. The conversation also digs into the role of Visual Studio as a project management tool, and its integration with cloud, GitHub, and more!

How has DevOps changed in 2025? Carl and Richard talk to Michael Levan about his experiences helping teams automate their development workflows, and dealing with all the details that help the entire team focus on providing customer value. Michael digs into the role of the new AI tools in facilitating better workflows around code, testing, deployment, telemetry, and more. Then the conversation turns to security - and the many challenges that exist to make applications that are secure when deployed, and help with the security challenges that happen while in operation!

How did the design of GitHub evolve? Carl and Richard speak with Diana Mounter about her experiences at GitHub, including her role as head of design. Diana discusses how she was drawn to GitHub as a designer and how her career evolved to lead design for the company. The conversation ranges over different design concepts, the Primer design language, and how to effectively combine design and development to achieve great results.

What's coming in C#14? Carl and Richard chat with Dustin Campbell about the next version of C#, discussing what it takes to continue advancing software development in the Microsoft ecosystem. Dustin discusses how features are selected from version to version, including long-developed features like extension members, which have been in development for years. The conversation also turns to Razor Pages, which Dustin helps contribute to, and the dynamic of what should be language, what should be framework, and what should be tooling. And there's much more to come!

How has application security evolved over the decades? Carl and Richard talk to Michael Howard about his experiences working in security at Microsoft. Michael discusses his current role as a member of the Red Team at Microsoft, which identifies security vulnerabilities within the organization by creating scenarios that black hats might employ, such as stealing tokens or hijacking financial transactions. The conversation examines how security continues to evolve, with improved tools, new attack surfaces, and increasingly serious attacks. It's an arms race, but one the good guys can win!

Can you improve a legacy application? What's the right way to go about it? Carl and Richard talk with Billy Hollis about his work updating legacy applications, starting with the most essential question: should you? Billy begins by defining what it means to be a legacy application and how, invariably, these applications are critical to the organization, so you have to tread lightly. Typically, the focus is on modernizing the client-side of the app, which brings us to the crux of the matter: Are the workflows of the company today well reflected in the older application? Lots of great thoughts from one of the longest-serving guests of .NET Rocks!