Aider

Aider uses FreeTheAI through its OpenAI compatible setting: two environment variables and the openai/ model prefix.

Category: Coding tools. Before you start, you need a FreeTheAI account, an API key, and today's check-in.

Settings

Setting	Value
OPENAI_API_BASE	https://api.freetheai.org/v1
OPENAI_API_KEY	Your FreeTheAI key (ftai_..., 53 characters)
--model	openai/fta/zai/glm-5.3

Steps

Set the environment variables

On macOS and Linux:

export OPENAI_API_BASE=https://api.freetheai.org/v1
export OPENAI_API_KEY=ftai_your_key_here

On Windows

Run these, then open a new terminal:

setx OPENAI_API_BASE https://api.freetheai.org/v1
setx OPENAI_API_KEY ftai_your_key_here

Start Aider

In your project folder, add openai/ in front of the FreeTheAI model ID:

aider --model openai/fta/zai/glm-5.3

Tips

• Aider warns about unknown model settings for fta/ models. It still works; the warning is about context size defaults.

Common questions

Why does Aider need openai/ before the model?

The prefix tells Aider to use the OpenAI compatible client with your OPENAI_API_BASE.

More help

• Every API error and its fix
• Limits and the daily reset
• Aider website and source code

How this guide was checked

Checked against Aider's docs (OpenAI compatible APIs) on 2026-09-29.