Bring Your Own Subscription · BYOS
Build C# and .NET with the AI subscription you already have. iolys is an agent harness for Visual Studio: connect a supported coding agent, work in your solution, and review its changes.
Free for personal and commercial use. AI provider costs remain separate.
AI providers for C# and .NET in Visual Studio 2026
Claude
Featured
Codex
Featured
Kiro
Featured
DeepSeek
Featured
OpenRouter
Featured
Ollama
Kimi
OpenCode Go
OpenCode Zen
Databricks Unity Catalog
Gemini
Your subscription → your .NET solution
Start with the AI access you already pay for. Here is the path with Codex; other supported agents have their own connection steps and eligibility rules.
Use a ChatGPT account whose plan includes Codex access. Check the provider's plan conditions and quotas before connecting.
Check the Codex connection →Install iolys, restart Visual Studio 2026, and open your solution. Open View → Iolys Chat, configure Codex, and sign in through its CLI.
Install the extension →Select a model, Agent mode, and a permission level. Ask for a focused change, let the agent build and test, then review the diff.
All currently available iolys features are free for personal and commercial use. Your provider's costs, eligibility, quotas, and terms still apply.
Built for Visual Studio
Install iolys from the Visual Studio Marketplace, restart Visual Studio 2026, and open your C# or .NET solution. Your existing projects and tools stay at the center of your work.
View on the Marketplace
Navigate AI providers and coding agents from one Visual Studio workspace…
iolys
Connect the right coding agent to your C# and .NET solution without leaving Visual Studio.
Bring Your Own Subscription · BYOS
Visual Studio’s Bring Your Own Model (BYOM) flow expands model choice through provider keys, deployments, and local endpoints. For metered cloud routes, usage stays billed by the provider. iolys also reuses eligible subscriptions through supported agent CLIs, an OpenCode Go API key, or your organization's Databricks workspace.
Provider eligibility and limits apply. API-key, enterprise, and local-model connections remain available when they fit better.
Explore BYOM vs BYOS
Use the credits or quotas included with an eligible plan through a supported provider CLI or an OpenCode Go API key, or reach the models your organization already pays for in its Databricks workspace.
No mandatory second API account
Run Ollama locally with no provider bill, or provide DeepSeek, OpenRouter, or OpenCode Zen API credentials and pay for model usage whenever that route fits better.
Your infrastructure. Provider billing may apply.The problem
AI models improve quickly, but switching providers still pushes C# developers toward another editor, another interface, and another workflow outside Visual Studio 2026.
Your .NET development workflow becomes tied to one vendor’s roadmap, models, and pricing.
Powerful agents live outside Visual Studio 2026, separating the work from the code.
Private and self-hosted options rarely fit naturally into the Visual Studio 2026 workflow.
The harness around your agent
iolys connects the agent to your development workflow: independent tasks, reusable specialists, and a build-and-test loop you can inspect.
Explore all iolys capabilities →Work on a C# fix and an independent feature in separate Git worktrees and branches. Open each workspace in its own Visual Studio instance to keep files and build state separate.
Try a parallel workflow →Define a C# reviewer or test writer with reusable instructions and selected tools. Share workspace agents through version-controlled .github/agents files.
Let the agent inspect compiler diagnostics, run builds and tests, and refine its changes. Review tool activity and file diffs, with permissions under your control.
Freedom by design
Your provider strategy should match the task—not the limitations of an extension.
Choose an eligible subscription, a metered API, or a local endpoint to match your task and the access you already have.
Reuse eligible plans through supported provider CLIs, an OpenCode Go API key, or your organization's Databricks workspace.
Point iolys at OpenAI-compatible services or a Databricks Unity Catalog workspace and choose the right endpoint.
Work through Ollama without sending every task to a cloud provider.
Why iolys exists
Most AI coding innovation has centered on VS Code, while developers building C# and .NET applications in Visual Studio 2026 remain tied to a much narrower set of choices. iolys was built to change that.
Instead of asking developers to change tools whenever a better model appears, iolys lets the AI change behind a consistent, trustworthy Visual Studio 2026 experience.
Looking for a GitHub Copilot alternative for Visual Studio? →FAQ
Yes. iolys is a Visual Studio 2026 extension for C# and .NET that supports Claude, Codex, Kiro, Ollama, DeepSeek, Kimi, OpenRouter, OpenCode Go, OpenCode Zen, Databricks Unity Catalog, and Gemini. Connect supported provider CLIs, API keys, enterprise endpoints, or local models, then choose a provider and model in the same workspace. Provider access and usage costs remain separate.
BYOS is the iolys approach to working from a subscription you already pay for: an eligible AI provider plan reused through its supported CLI, an OpenCode Go subscription connected with its API key, or the Databricks workspace your organization already holds. Seven of the eleven iolys routes qualify. Provider eligibility and limits still apply.
BYOM expands model choice by connecting a model deployment, local endpoint, or provider API key. BYOS reuses an eligible subscription through a supported CLI, an OpenCode Go API key, or an existing Databricks workspace. An API key can authenticate subscription access as well as metered usage.
Install iolys in Visual Studio 2026, download the Codex CLI from Manage Providers, and sign in with your ChatGPT account. When your plan includes Codex access, iolys uses that access from your C# or .NET solution and the usage counts toward that plan's Codex allowance.
Yes. iolys connects the official Claude Code CLI to Visual Studio 2026, so eligible Claude account access works from the active C# or .NET solution. Installation and sign-in happen in the iolys provider panel.
Yes. iolys connects compatible models served by Ollama on your own machine or network, so tasks do not have to be sent to a cloud provider. Results depend on the model and the available hardware.
Yes. iolys works from the active Visual Studio 2026 solution, including C# projects, .NET applications, libraries, tests, and multi-project solutions.
iolys targets the Visual Studio 2026 IDE on 64-bit Windows. You need access to a supported AI provider or a local Ollama instance. Git is required for isolated parallel workspaces. Visual Studio Code is a separate editor; iolys is an extension for the Visual Studio IDE.
Yes. All currently available iolys features are free for personal and commercial use. AI provider subscriptions, API usage, and infrastructure costs remain separate.
No. iolys is a provider-independent workspace that connects Visual Studio 2026 to models, agents, CLIs, and compatible APIs.
Yes. iolys reuses eligible account access through supported provider CLIs, an OpenCode Go subscription through its API key, and your organization's existing Databricks workspace. Provider eligibility and usage limits still apply.
Yes. iolys supports Ollama and is designed to work with local and self-hosted model routes alongside cloud providers.
No. The extension is built specifically for Visual Studio 2026 so conversations, workspace context, and agent activity stay close to your code.
Yes. iolys is distributed as a VSIX extension for Visual Studio 2026 on 64-bit Windows. Install the VSIX from the Visual Studio Marketplace, or from Extensions > Manage Extensions inside Visual Studio, restart the IDE, then connect a provider from the Manage Providers panel.
The provider and model change; the core iolys interface, navigation, permission flow, and workspace context remain consistent.
Choose your next model, not your next workflow
One Visual Studio 2026 extension for C#, .NET, and the changing world of AI providers.
Get iolys for Visual Studio 2026