Connecting Codex CLI to NordRouter

Experimentally

Codex uses the Responses API. The custom provider is supported by Codex itself, but the specific model via NordRouter needs to be checked separately: the usual /chat/completions is not enough for this client.

Recommended option

UseOpenCodex: It locally translates API Codex Responses into NordRouter supported format /chat/completions.

In %USERPROFILE%\.codex\config.toml on Windows or ~/.codex/config.toml on macOS/Linux:

model = "anthropic/claude-sonnet-4.6"
model_provider = "nordrouter"

[model_providers.nordrouter]
name = "NordRouter"
base_url = "https://nordrouter.com/v1"
env_key = "NORDROUTER_API_KEY"
wire_api = "responses"

Then set the variable NORDROUTER_API_KEY and run Codex in the test folder. If 404 comes to /responses, use Cline, Roo Code, OpenCode or Claude Code - they work through supported API formats.

Official information:Custom model providers.

All programs