Bring Your Own Model
Connect a model deployment or endpoint selected and controlled by you or your organization.
You bring the intelligence.
Bring Your Own Model · BYOM
Bring your own model.
Choose how you access it.
BYOM gives C# and .NET developers more control over the model behind their work. iolys goes further: bring a deployment, an API key, a local endpoint, or eligible subscription access into Visual Studio 2026.
BYOMModel or deploymentFoundry, Databricks, Ollama
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BYOKProvider API keyCloud or compatible endpoint
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BYOSEligible subscriptionCLI, OpenCode Go, or Databricks
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ONE WORKSPACEVisual Studio 2026C# and .NET
Three access routes
Model choice and payment choice are different decisions.
These terms are often mixed together. The practical distinction is what you bring to the tool and who controls access, usage, and billing.
Bring Your Own Key
Authenticate directly with a provider API key. The provider plan determines whether usage draws from a subscription, prepaid credits, or pay-as-you-go billing.
You bring the API account.Bring Your Own Subscription
Use account access, credits, or quotas from an eligible plan through a supported provider CLI, an OpenCode Go API key, or the Databricks workspace your organization already pays for.
You bring the plan you already use.BYOM vs BYOK vs BYOS
Choose the route that matches your constraints.
| Route | What you bring | Typical connection | Usage ownership | Best fit |
|---|---|---|---|---|
| BYOM | Model deployment or endpoint | Foundry, Databricks, self-hosted, or local | Your infrastructure or provider account | Governance, control, custom deployments |
| BYOK | Provider API key | Cloud or OpenAI-compatible API | Subscription allowance, prepaid credits, or pay-as-you-go, depending on the provider plan | Direct API access and model flexibility |
| BYOS | A subscription you already pay for | Supported provider CLI sign-in, an OpenCode Go API key, or your organization's Databricks workspace | Included access, credits, or quotas subject to provider terms | Reusing a plan you already pay for |
Microsoft Visual Studio BYOM
A welcome step toward model choice.
Microsoft’s current Visual Studio BYOM preview connects Microsoft Foundry deployments or keys from supported providers in Agent Mode. That expands model choice and lets organizations keep approved deployments and governance.
BYOM does not define one billing model. Local models can run on your own machine; hosted deployments consume the infrastructure or provider account behind them. iolys complements those routes with BYOS through supported CLIs, an OpenCode Go API key, and your organization's Databricks workspace.
Read Microsoft’s current BYOM announcement ↗Use every useful route
iolys makes BYOM and BYOS complementary.
Choose per task without rebuilding your Visual Studio workflow.
Subscription-backed agents
Use eligible Claude, Codex, Kiro, Kimi, or Gemini access through supported provider CLIs.
Explore BYOS →Governed deployments
Connect chat-capable Databricks Unity Catalog Model Serving endpoints selected by your organization.
Explore Databricks →Provider keys
Use your OpenCode Go subscription, DeepSeek, OpenRouter, OpenCode Zen, and compatible endpoints with credentials you control.
Explore providers →Models on your machine
Run compatible Ollama models locally when privacy, cost, or offline access matters.
Explore Ollama →BYOM FAQ
Bring the right access route to your .NET work.
What does Bring Your Own Model (BYOM) mean?
BYOM means connecting a model deployment or endpoint that you or your organization controls to the development experience you already use.
Does BYOM always mean pay-as-you-go billing?
No. A local or self-hosted model can avoid a metered cloud-model bill. When BYOM uses a cloud provider API key or hosted deployment, usage and billing usually remain with that provider or infrastructure account.
What is the difference between BYOM, BYOK, and BYOS?
BYOM brings a model or deployment, BYOK brings a provider API key, and BYOS brings a subscription you already pay for. BYOS includes eligible plans through supported provider CLIs, OpenCode Go through its API key, and your organization's Databricks workspace. BYOK and BYOS can overlap: OpenCode Go uses an API key for subscription access.
Do I need a separate API account to use AI in Visual Studio 2026?
Not always. With iolys, seven of the eleven routes reuse a subscription you already pay for, so no second pay-as-you-go API account is required for those. OpenCode Go uses an API key for its subscription, while DeepSeek, OpenRouter, and OpenCode Zen API keys use prepaid credits or pay-as-you-go. Ollama needs no account at all.
Can I use an existing AI subscription with iolys?
Yes. Use an eligible plan through its supported provider CLI, connect your OpenCode Go subscription with its API key, or use your organization's Databricks workspace. Provider availability, credits, quotas, and usage limits remain governed by that provider.
Can I use a local model instead?
Yes. iolys supports local Ollama endpoints, so you can use compatible models running on infrastructure you control.
What do I install to bring my own model into Visual Studio?
One VSIX: iolys. The iolys VSIX for Visual Studio 2026 is the only install needed, and your BYOM, BYOK, or BYOS route is then configured inside the Manage Providers panel rather than through an extra extension.
Does iolys include model usage?
No. All currently available iolys features are free for personal and commercial use. AI provider subscriptions, API usage, enterprise endpoints, and local infrastructure costs remain separate.
Your model. Your key. Your subscription.
Bring your AI access to Visual Studio 2026.
One provider-independent workspace for C#, .NET, BYOM, BYOK, and BYOS.
Get iolys for Visual Studio 2026