Claude Code

Claude Code can talk to an Anthropic-compatible API at a custom address. Set two environment variables — the agent then works as usual, no VPN.

Install

You'll need Node.js 18 or newer. Claude Code itself installs with one command:

terminal

npm install -g @anthropic-ai/claude-code

Verify the version: claude --version. Grab a cai-... key from the API keys section.

Configure via environment variables

Claude Code reads the base URL and token from the environment:

macOS / Linux

Add to ~/.zshrc (or ~/.bashrc / ~/.bash_profile):

~/.zshrc

export ANTHROPIC_BASE_URL="https://api.cheapai.io"
export ANTHROPIC_AUTH_TOKEN="cai-..."

Restart the terminal (or source ~/.zshrc) and run:

terminal

claude   # everything else as usual

Windows (PowerShell)

powershell

[Environment]::SetEnvironmentVariable("ANTHROPIC_BASE_URL", "https://api.cheapai.io", "User")
[Environment]::SetEnvironmentVariable("ANTHROPIC_AUTH_TOKEN", "cai-...", "User")

Close and reopen PowerShell, then run claude.

Picking a model

The model name is the same as in the catalog. Pass it on the command line:

terminal

claude --model claude-3-5-sonnet

Or pin the default model in ~/.claude/settings.json:

~/.claude/settings.json

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.cheapai.io",
    "ANTHROPIC_AUTH_TOKEN": "cai-..."
  },
  "model": "claude-3-5-sonnet"
}

This keeps the config in a single file, no env vars needed.

Project-level config

To give a specific repository its own settings — drop a .claude/settings.json with the same content next to it. You can commit this file (without the key — keep it in the environment), and the whole team will run through the gateway with the same model.

First-run connection error

On the very first start Claude Code sometimes shows something like Unable to connect to Anthropic services or Failed to connect to api.anthropic.com — that's the onboarding check, which doesn't yet account for a custom BASE_URL. Open ~/.claude.json and add the field: