Use GitHub Copilot with llmapi.cheap

Run GitHub Copilot on Gemini 3.8 Flash, Claude Sonnet 4.6, Claude Opus 4.6 or GPT-OSS with a single llmapi.cheap key. Plans start at $2 a month, and there is a free one-hour trial.

Protocol: Anthropic / OpenAI Chat · Config: VS Code user folder/chatLanguageModels.json

Fastest: one command

The setup command finds GitHub Copilot on your machine, writes its configuration with your key and sets Gemini 3.8 Flash (high) as the default model. It needs no Node.js. Sign up first: your key is created automatically, and the dashboard shows this command with the key already filled in.

macOS / Linux

curl -fsSL https://llmapi.cheap/install.sh | sh

Windows (PowerShell)

irm https://llmapi.cheap/install.ps1 | iex

Manual setup

VS Code: the setup command adds llmapi as a custom endpoint. By hand, open the Copilot Chat model picker → Manage Models → Add, choose "OpenAI compatible" and enter:

URL:     https://llmapi.cheap/v1/chat/completions
API key: YOUR_API_KEY
Model:   gemini-3.8-flash-high

Visual Studio and JetBrains Copilot have the same Manage Models screen. Business and Enterprise organisations can turn custom models off. For the Copilot CLI:

export COPILOT_PROVIDER_BASE_URL=https://llmapi.cheap/v1 COPILOT_PROVIDER_API_KEY=YOUR_API_KEY COPILOT_MODEL=gemini-3.8-flash-high

Endpoints

Use the base URL that matches the protocol your tool speaks.

OpenAI: https://llmapi.cheap/v1
Anthropic: https://llmapi.cheap
Gemini: https://llmapi.cheap/v1beta
Models: https://llmapi.cheap/v1/models

Model IDs

Any of these work wherever GitHub Copilot asks for a model name. Gemini 3.8 Flash (high) is the default the setup command picks.

Model ID	Model
`gemini-3.8-flash-high`	Gemini 3.8 Flash, high reasoning (default)
`gemini-3.8-flash`	Gemini 3.8 Flash, medium reasoning
`gemini-3.8-flash-low`	Gemini 3.8 Flash, low reasoning
`gemini-3.1-pro-high`	Gemini 3.1 Pro, high reasoning
`gemini-3.1-pro-low`	Gemini 3.1 Pro, low reasoning
`gemini-3-flash`	Gemini 3 Flash
`claude-sonnet-4-6`	Claude Sonnet 4.6
`claude-opus-4-6`	Claude Opus 4.6
`gpt-oss-120b`	GPT-OSS 120B

Troubleshooting

401 / invalid key: check the key starts with sk-llm- and has no extra spaces. Create a new one under Dashboard → API keys if needed.
Model not allowed: the free trial covers the Gemini models; Claude and GPT-OSS come with any paid plan.
404 on requests: OpenAI-style tools need https://llmapi.cheap/v1; Anthropic-style tools need https://llmapi.cheap without /v1.