Aider vs OpenAI Codex CLI
Aider and OpenAI Codex CLI are both terminal AI coding tools. Here's how they line up on the things that actually decide it — price, platform, and what they plug into.
| Aider | OpenAI Codex CLI | |
|---|---|---|
| Pricing | Free | Free tier |
| Platform | windows, mac, linux | windows, mac, linux |
| Works with | claude, chatgpt, gemini | chatgpt |
| In one line | Open-source AI pair programmer that runs in your terminal — paste a task, it edits your files and auto-commits the changes to git. | OpenAI's free, open-source terminal coding agent — runs agentic file editing, shell commands, and multi-step tasks powered by o4-mini. |
Which should you pick?
On budget alone, Aider is the lower-cost entry (free), so it's the safer place to start if you're not ready to pay. They both work with chatgpt, so if that's your setup either one fits. For the full picture, read the reviews below — the verdict is where the real difference shows up.