Codex CLI Free 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.

Website Source code API reference

Before you start

Create a free account and an API key. Create an account
Check in once a day to unlock the free models. Daily check-in
Pick a model ID from the models page. Browse models

Settings

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

Steps

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"
```

Edit config.toml

Open ~/.codex/config.toml (on Windows, %USERPROFILE%\.codex\config.toml) and add:

toml

model = "fta/zai/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"

Run Codex
Start codex. To switch models, change model = "..." to any fta/ ID and restart.

How this guide was checked: Tested with the current Codex CLI on 2026-09-29 (Responses streaming and tool calls through FreeTheAI).

Tips

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

Troubleshooting

Does FreeTheAI support the Responses API Codex needs?

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

Common errors

401: the key is wrong or incomplete. Paste the whole key.
403: check in for today, or confirm your email.
404: the model ID or URL is wrong.
429: daily limit reached, or too many requests at once.

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