GitHub Copilot Setup
Point GitHub Copilot Chat at Flatrouter with the OAI Compatible Provider extension, and use Claude, GPT, Gemini and more.
With the VS Code extension OAI Compatible Provider for Copilot, you can send GitHub Copilot Chat through Flatrouter and use Claude, GPT-5.6, Gemini and other models in the editor you already know.
The extension needs a GitHub Copilot Individual subscription. Copilot Business and Enterprise are not supported yet. If you do not have a Copilot subscription, use Claude Code, Codex CLI or Cherry Studio instead.
Requirements
- A Flatrouter account and an API key (get one here)
- VS Code installed
- A valid GitHub Copilot Individual subscription (Business / Enterprise are not supported)
Setup
Step 1: install the extension
In the VS Code Marketplace, search for OAI Compatible Provider for Copilot (author: Johnny Zhao) and click Install.
Step 2: open the configuration UI
Open the command palette with Cmd+Shift+P (macOS) / Ctrl+Shift+P (Windows/Linux) and run:
OAICopilot: Open Configuration UIStep 3: fill in global configuration
In Global Configuration, set the following, then click Save Global Configuration:
| Field | Value |
|---|---|
| Global Base URL | https://api.flatrouter.com/v1 |
| Global API Key | Your Flatrouter API key |
Step 4: add a provider
In Provider Management, click Add Provider, fill in the new row, then click Save:
| Field | Value |
|---|---|
| Provider ID | flatrouter |
| Base URL | https://api.flatrouter.com |
| API Key | Your Flatrouter API key |
| API Mode | Anthropic |
Step 5: add models
In Model Management, click Add Model, fill in the fields, then click Save Model:
| Field | Value |
|---|---|
| Provider ID | flatrouter |
| Model ID | A model name such as anthropic/claude-opus-4.5 |
Repeat to add more models. Copy IDs from the Flatrouter model catalog.
Step 6: pick the model in chat
Open the Copilot Chat panel, click the model picker, turn Auto off, and select the Flatrouter model you just added under Other Models.
If it does not show up, click Manage Models… to open the model list.
Step 7: confirm and start chatting
In the Language Models panel, added Flatrouter models appear under the OAI Compatible group. Select the model in the chat box and start talking.
Recommended models
See the model catalog for current recommendations.
FAQ
Q: I cannot find the extension in the Marketplace
Search for the full name OAI Compatible Provider for Copilot, or search for the author Johnny Zhao.
Q: The command palette has no OAICopilot: Open Configuration UI
Make sure the extension is installed and enabled. After install you may need to reload the VS Code window (Cmd+Shift+P → Reload Window).
Q: The model I added does not show up in chat
Turn Auto off in the model picker and look under Other Models, or click Manage Models… to check that the model was saved.
Q: I get "Invalid API Key" or the request fails
Check:
- Global Base URL is
https://api.flatrouter.com/v1(no trailing slash) - The API key was copied in full from the Flatrouter console, with no extra spaces
- The provider's API Mode is set to
Anthropic
Q: Tab completion still uses Copilot's official models
That is expected. OAI Compatible Provider currently only affects Copilot Chat. Tab completion stays under GitHub Copilot's official control.
Q: I am on Copilot Business / Enterprise. Can I use this?
Not yet. The extension only works for GitHub Copilot Individual. Business and Enterprise need a later release.