---
title: "Codex CLI API: Use FreeTheAI Models in Codex"
description: "Configure OpenAI Codex CLI to use AI models through FreeTheAI's Responses API. A tested config.toml with a custom model provider."
url: https://freetheai.org/setup/codex
language: en
updated: 2026-09-29
---

# Codex CLI API: Use FreeTheAI Models in Codex

Codex CLI talks to FreeTheAI through the OpenAI Responses API. Add FreeTheAI as a model provider in config.toml and keep the key in an environment variable.

## Settings

- base_url: `https://api.freetheai.org/v1`
- wire_api: `responses`
- env_key: `FREETHEAI_API_KEY`

## Steps

1. **Save your key in an environment variable.** On Windows run the first line and open a new terminal; on macOS and Linux add the second line to your shell profile.

```text
setx FREETHEAI_API_KEY "ftai_your_key_here"
export FREETHEAI_API_KEY="ftai_your_key_here"
```
2. **Edit config.toml.** Open ~/.codex/config.toml (on Windows, %USERPROFILE%\.codex\config.toml) and add:

```toml
model = "glm-5.3"
model_provider = "freetheai"

[model_providers.freetheai]
name = "FreeTheAI"
base_url = "https://api.freetheai.org/v1"
env_key = "FREETHEAI_API_KEY"
wire_api = "responses"
```
3. **Run Codex.** Start codex. To switch models, change model = "..." to any ID freetheai.org/models lists and restart.

## Tips

- Codex only speaks the Responses API now; wire_api = "chat" is refused by current versions.
- glm-5.3 and kimi-k3.1-pro handle tool calls well.

## Troubleshooting

**Does FreeTheAI support the Responses API Codex needs?**

Yes. /v1/responses is translated for every chat model, streamed or not. It was tested with Codex on 2026-09-29.

Checked: Tested with the current Codex CLI on 2026-09-29 (Responses streaming and tool calls through FreeTheAI).