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Issue 001 / A living technical almanac

Rankings never sold

Coding Agents · Head-to-head

gemini-cli vs OpenAI Codex

gemini-cli and OpenAI Codex are both coding agents. gemini-cli is An open-source AI agent that brings the power of Gemini directly into your terminal, while OpenAI Codex is openAI's cloud software engineering agent that works on many tasks in parallel. Here's an independent, side-by-side look at how they compare — and which fits.

gemini-cli

Agent· Open source

An open-source AI agent that brings the power of Gemini directly into your terminal.

Visit gemini-cli
OpenAI Codex

Agent· Paid product

OpenAI's cloud software engineering agent that works on many tasks in parallel.

Visit OpenAI Codex

Bottom line

gemini-cli and OpenAI Codex take different routes to the same job: one is a commercial product, the other open-source and self-hostable. Choose based on whether you want a managed experience or full control.

Side by side

Specgemini-cliOpenAI Codex
TypeAgentAgent
ModelOpen sourceCommercial
PricingOpen sourcePaid product
GitHub stars105,872
LanguageTypeScript
LicenseApache-2.0
Last activityJul 2026

Key differences

  • OpenAI Codex is a commercial product; gemini-cli is open-source and self-hostable.
  • Pricing model differs — gemini-cli is open source, OpenAI Codex is paid product.

Choose gemini-cli if

you want an open-source, self-hostable option you control.

Choose OpenAI Codex if

Running many delegated engineering tasks in parallel in the cloud..

About gemini-cli

An open-source AI agent that brings the power of Gemini directly into your terminal.

Full gemini-cli profile →

About OpenAI Codex

OpenAI's cloud software engineering agent that works on many tasks in parallel.

Full OpenAI Codex profile →

Frequently asked

What's the main difference between gemini-cli and OpenAI Codex?
OpenAI Codex is a commercial product; gemini-cli is open-source and self-hostable.
Is gemini-cli or OpenAI Codex better?
Neither is universally better. gemini-cli is the stronger fit for an open-source, self-hostable option you control; OpenAI Codex for Running many delegated engineering tasks in parallel in the cloud. Use the side-by-side specs to decide by your own constraints.
Is gemini-cli or OpenAI Codex free?
gemini-cli is free to run and self-host; OpenAI Codex is a paid product.
Which is more popular, gemini-cli or OpenAI Codex?
We rank open-source projects by GitHub adoption, but at least one of these is a commercial product and stars don't measure commercial adoption — so compare them on capabilities and pricing instead.
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