OpenAI Codex vs Gemini CLI
OpenAI Codex vs Gemini CLI (Coding Agents (CLI & Cloud)). Agent test scores: OpenAI Codex 7.4/10, Gemini CLI 6.1/10. OpenAI Codex scored 1.3 higher overall in our separate rubric v0.1 tests (editions and tasks can differ — see Edition tested and the notes below). Pricing: OpenAI Codex — Included in every ChatGPT plan (Free, Go, Plus, Pro, Business, Enterprise, Edu); usage limits vary by plan. Codex Cloud needs Plus, Pro, Business, Enterprise or Edu. Plus/Pro buyers can add credits. Plan prices on chatgpt.com/pricing; Gemini CLI — Requires paid Gemini API key, Vertex AI, or Gemini Code Assist Standard/Enterprise.
Every fact on this page comes from our tool records and test logs. Last updated:
- VibeToolRank score
- 7.4/10
- Last tested
- 2026-10-16
- Runs
- 3 runs
- Outcome score
- 8/10
- Edition tested
- Codex CLI 0.163.0 with OpenRouter free model cohere/north-mini-code:free (no ChatGPT login; not OpenAI's models)
- Free plan, as measured
- 33K–262K tokens per bugfix run on a free OpenRouter model, $0
- Free plan
- Yes: Codex CLI, IDE extension and app on ChatGPT Free and Go with plan usage limits (no Codex Cloud)
- Price
- Included in every ChatGPT plan (Free, Go, Plus, Pro, Business, Enterprise, Edu); usage limits vary by plan. Codex Cloud needs Plus, Pro, Business, Enterprise or Edu. Plus/Pro buyers can add credits. Plan prices on chatgpt.com/pricing
- Pricing checked
- 2026-11-02
- VibeToolRank score
- 6.1/10
- Last tested
- 2026-10-17
- Runs
- 3 runs
- Outcome score
- 8/10
- Edition tested
- Gemini CLI 0.64.0, free-tier Gemini API key, default model gemini-3.8-flash
- Free plan, as measured
- One todo-app attempt used up the free daily quota (20 requests/day on gemini-3.8-flash); the next day's runs hit the same limit
- Free plan
- No longer via Google sign-in (consumer users moved to Antigravity CLI June 18, 2026); free API-key quota unclear
- Price
- Requires paid Gemini API key, Vertex AI, or Gemini Code Assist Standard/Enterprise
- Pricing checked
- 2026-10-16
Side by side
| Field | OpenAI Codex | Gemini CLI |
|---|---|---|
| What it is | OpenAI CodexOpenAI's coding agent for CLI, IDE and cloud. | Gemini CLIOpen-source terminal agent from Google; consumer users moved to Antigravity CLI in June 2026. |
| Pricing | OpenAI CodexIncluded in every ChatGPT plan (Free, Go, Plus, Pro, Business, Enterprise, Edu); usage limits vary by plan. Codex Cloud needs Plus, Pro, Business, Enterprise or Edu. Plus/Pro buyers can add credits. Plan prices on chatgpt.com/pricing | Gemini CLIRequires paid Gemini API key, Vertex AI, or Gemini Code Assist Standard/Enterprise |
| Free tier | OpenAI CodexYes: Codex CLI, IDE extension and app on ChatGPT Free and Go with plan usage limits (no Codex Cloud) | Gemini CLINo longer via Google sign-in (consumer users moved to Antigravity CLI June 18, 2026); free API-key quota unclear |
| Pricing verified | OpenAI Codex2026-11-02 | Gemini CLI2026-10-16 |
| Edition tested | OpenAI CodexCodex CLI 0.163.0 with OpenRouter free model cohere/north-mini-code:free (no ChatGPT login; not OpenAI's models) | Gemini CLIGemini CLI 0.64.0, free-tier Gemini API key, default model gemini-3.8-flash |
| Tested on | OpenAI Codex2026-10-16 | Gemini CLI2026-10-17 |
| Outcome score | OpenAI Codex8 | Gemini CLI8 |
| Speed score | OpenAI Codex8 | Gemini CLI6 |
| Cost score | OpenAI Codex9 | Gemini CLI6 |
| Developer experience score | OpenAI Codex6 | Gemini CLI4 |
| Reliability score | OpenAI Codex5 | Gemini CLI3 |
| Overall score | OpenAI Codex7.4 | Gemini CLI6.1 |
What our tests found
OpenAI Codex
Using a custom OpenRouter provider and a small free model, Codex CLI fixed our seeded cart bug in 2 of 3 runs (19-76s). In the failed run the model issued an apply_patch call that Codex rejected. Token use was high (33K-262K). Not tested with OpenAI's own models.CLI, free model
- Runs without a ChatGPT login through any Responses-compatible provider
- Fixed the bug in 2 of 3 runs on a free model at $0
- Sandboxed workspace-write mode for unattended runs
- With a free model, 1 of 3 runs failed on an unsupported apply_patch call
- Used 33K-262K tokens per run, versus about 2K for Aider
- Flags change between versions (--full-auto removed) and the chat wire API is no longer supported
- Our test did not use OpenAI's own models
- Codex cloud (the web agent) needs ChatGPT Plus, Pro or Business; the Go plan redirects to an upgrade (2026-10-16)
Who it’s for: Developers in the OpenAI ecosystem who want a terminal agent; it works best with OpenAI models via a ChatGPT plan or API key.
Gemini CLI
Google-account login for individuals no longer works (the CLI says to migrate to Antigravity), so we used a free-tier API key. Run 1 (16 Oct 2026) wrote a complete todo app in about 5 minutes, then hit the free tier's 20-requests-per-day limit for gemini-3.8-flash. We re-ran on 17 Oct 2026: runs 2 and 3 both failed immediately with the same 429 quota error and wrote no files. We verified the run-1 app ourselves in headless Chrome: add, complete, delete, filters, reload persistence and the mobile layout all passed.CLI, free API tier
- The one app it finished passed every check in our own headless browser test, including mobile
- Single command, headless mode with JSON output
- Free API key tier, no card
- Google-account login for individuals fails with 'client no longer supported ... migrate to Antigravity'
- Free tier allowed only 20 requests per day on gemini-3.8-flash; one small app used them all
- Re-test on 17 Oct 2026: runs 2 and 3 both exited 173 with quota exhausted before writing any files
- The saved Google-login setting overrides GEMINI_API_KEY until you change settings
Who it’s for: Developers with a paid Gemini API key or Vertex AI who want an open-source terminal agent; casual free use is now very limited.
Verdict
Scores use rubric v0.1 from separate runs. Editions and tasks can differ (see Edition tested and What our tests found); some tests were a single run, which caps reliability scores. Overall: OpenAI Codex 7.4, Gemini CLI 6.1. Check the free-tier limits above against your project before choosing.
FAQ
Which is better, OpenAI Codex or Gemini CLI?
In our tests OpenAI Codex scored higher overall (7.4/10 vs 6.1/10). Scores use the same rubric (v0.1) but came from separate runs; editions and tasks may differ (see Edition tested and test summaries), so check the per-dimension scores for what matters to you.
Is OpenAI Codex free?
Yes: Codex CLI, IDE extension and app on ChatGPT Free and Go with plan usage limits (no Codex Cloud) (pricing checked 2026-11-02).
Is Gemini CLI free?
No longer via Google sign-in (consumer users moved to Antigravity CLI June 18, 2026); free API-key quota unclear (pricing checked 2026-10-16).
How much does OpenAI Codex cost compared with Gemini CLI?
OpenAI Codex: Included in every ChatGPT plan (Free, Go, Plus, Pro, Business, Enterprise, Edu); usage limits vary by plan. Codex Cloud needs Plus, Pro, Business, Enterprise or Edu. Plus/Pro buyers can add credits. Plan prices on chatgpt.com/pricing. Gemini CLI: Requires paid Gemini API key, Vertex AI, or Gemini Code Assist Standard/Enterprise.
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Scores come from our own tests and are never for sale; sponsored placements are always labelled. Some links are affiliate links (currently Railway). Disclosure