Codex CLI vs Gemini CLI
Side-by-side comparison of Codex CLI and Gemini CLI. Pricing, features, best use cases, and honest verdict from a developer who has tested both.
Key Takeaways
- +Codex CLI is better for: ai, coding, cli
- +Gemini CLI is better for: ai, coding, cli
- ~Both are ai coding tools. Your choice depends on workflow preference and team setup.
Codex CLI
OpenAI's open-source terminal coding agent built in Rust. Runs locally, reads your repo, edits files, and executes commands. Powered by o3 and o4-mini models.
Gemini CLI
FreeGoogle's open-source coding CLI. Free tier with Gemini 2.5 Pro. Supports tool use, file editing, shell commands. 1M token context window.
Feature Comparison
| Feature | Codex CLI | Gemini CLI |
|---|---|---|
| Category | AI Coding | AI Coding |
| Type | CLI Tool | CLI Tool |
| Pricing | See website for pricing | Free tier available |
| Best For | AI-powered development | Large-context CLI coding with Gemini |
| Language / Platform | Any (CLI) | Any (CLI) |
| Open Source | Yes | Yes |
In Depth
Codex CLI
Codex CLI is OpenAI's open-source coding agent that runs directly in your terminal. Built in Rust for speed, it launches into a full-screen terminal UI where it reads your repository, makes edits, and runs commands as you iterate together. It brings the power of o3 and o4-mini into your local workflow with a conversational interface where you review every action in real time. Install via npm or Homebrew, authenticate with your ChatGPT account or API key, and you are coding. The codex-mini model is optimized specifically for low-latency code Q&A and editing. It is included with ChatGPT Plus, Pro, Business, Edu, and Enterprise plans at no additional cost. For developers who want OpenAI's models in a local terminal workflow rather than a browser, this is the tool.
Gemini CLI
Gemini CLI is Google's free, open-source terminal coding assistant. It connects to Gemini 2.5 Pro (1M token context window - the largest of any coding tool) and supports file editing, shell command execution, and MCP tool use. The free tier is generous enough for daily use. It's the best free alternative to Claude Code. My walkthrough video got 54,000 views. The 1M context window means it can ingest entire large codebases in a single prompt - something Claude Code and Codex can't do in one shot.
The Verdict
Both Codex CLI and Gemini CLI are strong tools in the ai coding space. The right choice depends on your workflow. Read the full review of each tool for a deeper dive, or watch the video walkthroughs to see them in action.
