> ## Content Index > Fetch the complete content index at: https://codetraveler.io/llms.txt > Use this file to discover other available public pages before exploring further. # Running On-Device LLMs in .NET MAUI with `Microsoft.Maui.Essentials.Ai` - URL: https://codetraveler.io/2026/08/24/running-on-device-llms-in-net-maui-with-microsoft-maui-essentials-ai/ - Published: 2026-08-24T09:00:02.000Z - Updated: 2026-08-24T18:04:59.000Z - Author: Brandon Minnick The fastest, cheapest, most private LLM call is the one that never leaves your phone. [Microsoft.Maui.Essentials.Ai](https://www.nuget.org/packages/Microsoft.Maui.Essentials.Ai?ref=codetraveler.io) makes it easy. This is Part 7 of our `Microsoft.Extensions.AI` series. Every LLM we've talked about thus far (Ollama, OpenAI, Azure) ran *somewhere else*. This week, our .NET MAUI app runs the built-in model on user's phone. You're welcome to skip the definitions and jump directly to the code below. ## What is Microsoft.Maui.Essentials.Ai? `Microsoft.Maui.Essentials.Ai` is a .NET MAUI NuGet Package that exposes on-device foundation models, like Apple Intelligence and Google's Gemini, as the same [IChatClient we learned about in Part 1](https://codetraveler.io/2026/07/16/adding-ai-to-your-net-app-with-ichatclient/). That means everything we've built in this series (streaming, chat history, function calling) works unchanged, except now it's offline, completely private, and costs $0 per token. ## Opt-into this Experimental Feature Just like `IImageGenerator` in [Part 3](https://codetraveler.io/2026/07/27/generating-images-in-net-with-iimagegenerator/), this package ships with the `[Experimental]` attribute while the team gathers feedback. 1. In the `csproj` file of your .NET MAUI app, suppress `MAUIAI0001`: ```xml $(NoWarn);MAUIAI0001 ``` > **Important:** Apple Intelligence requires iOS 26+ / macOS 26+ AND a physical device — it does not run on Simulators. Android and Windows support is planned, but not available yet. ## Code Now that we have those pesky definitions out of the way, let's write some code. You can find the [completed code sample here](https://github.com/Dometrain/from-zero-to-hero-microsoft-extensions-ai/tree/main/7.%20Using%20Mobile%20On-Device%20LLMs?ref=codetraveler.io). ### Prerequisites If you'd like to follow along, here are the steps. 1. A physical iPhone or Mac with Apple Intelligence enabled (iOS 26+ / macOS 26+) 2. Create a new [.NET MAUI app](https://learn.microsoft.com/dotnet/maui/get-started/first-app?ref=codetraveler.io) 3. Add the following NuGet Packages: - [Microsoft.Extensions.AI](https://www.nuget.org/packages/Microsoft.Extensions.AI?ref=codetraveler.io) - [Microsoft.Maui.Essentials.Ai](https://www.nuget.org/packages/Microsoft.Maui.Essentials.Ai?ref=codetraveler.io) > If you're unfamiliar with adding NuGet Packages, you can find more information [here](https://learn.microsoft.com/nuget/consume-packages/install-use-packages-visual-studio?ref=codetraveler.io#find-and-install-a-package). Now let's write some code. ### MauiProgram.cs Not every iPhone supports Apple Intelligence, so let's write our code to check at runtime for the proper operating system + physical device, then fall back to Ollama if the conditions aren't met. The cool thing is that the rest of our code only ever sees `IChatClient`: ```csharp using Microsoft.Extensions.AI; using Microsoft.Maui.Essentials.AI; using OllamaSharp; builder.Services.AddChatClient(static _ => { // Apple Intelligence requires iOS 26+ / macOS 26+ on a physical device if ((OperatingSystem.IsIOSVersionAtLeast(26) || OperatingSystem.IsMacCatalystVersionAtLeast(26)) && DeviceInfo.Current.DeviceType == DeviceType.Physical) { return CreateAppleIntelligenceChatClient(); } // Every other platform falls back to Ollama return new OllamaApiClient(new Uri("http://localhost:11434"), "qwen3.5"); }); static IChatClient CreateAppleIntelligenceChatClient() { #if IOS || MACCATALYST return new AppleIntelligenceChatClient(); #else throw new NotSupportedException("Apple Intelligence is only available on iOS + macOS"); #endif } ``` Now let's deploy to a physical iPhone, turn on Airplane Mode, and ask our chat app the question "What is .NET MAUI?": ``` .NET MAUI is a cross-platform framework for building native mobile and desktop apps with C# and XAML, from a single codebase. ``` It works! And with NO internet connection! The model ran entirely on the phone's Neural Engine. 🎉 ## Conclusion As .NET developers, we can now offer AI features that work offline, protect our users' privacy, and cost us nothing per request, thanks to `Microsoft.Maui.Essentials.Ai`. And we've only scratched the surface! The package also includes `NLEmbeddingGenerator`, an on-device `IEmbeddingGenerator` (iOS 13+) — which means the semantic search we built in [Part 2](https://codetraveler.io/2026/07/20/adding-semantic-search-to-net-apps-with-iembeddinggenerator/) can run on-device too. You can find the completed code sample here: [https://github.com/Dometrain/from-zero-to-hero-microsoft-extensions-ai](https://github.com/Dometrain/from-zero-to-hero-microsoft-extensions-ai/tree/main/7.%20Using%20Mobile%20On-Device%20LLMs?ref=codetraveler.io) Next week, we'll finally answer the most-asked question in AI: what is RAG, and how do we build one in C#? Make sure to subscribe to this blog so you don't miss it! 👇 To learn even more about `Microsoft.Extensions.AI`, check out my course on Dometrain: [Learn to use Microsoft.Extensions.AI in .NET - DometrainMaster the main AI abstraction library for .NET AI development![](https://storage.ghost.io/c/dc/c2/dcc2e43e-24f8-46bb-a899-9c446f3ef794/content/images/icon/favicon-32x32-b83f7d7f-3806-439c-8377-04e48907853c.png)DometrainBrandon Minnick![](https://storage.ghost.io/c/dc/c2/dcc2e43e-24f8-46bb-a899-9c446f3ef794/content/images/thumbnail/thumbnail-e14b39ca760b44139b0be9246741f6cb-9540ac16-a913-4060-8c7d-8028800af503.jpeg)](https://dometrain.com/course/from-zero-to-hero-microsoft-extensions-ai-in-dotnet?ref=codetraveler.io)