OpenAI Codex
—not yet run
Head-to-head · profiles checked Sep 29, 2026
OpenAI Codex vs Gemini CLI in 2026: which coding agent fits your setup
Pick OpenAI Codex for one agent across CLI, IDE, desktop app, web and iOS, bundled with ChatGPT from $8/mo on Go. Pick Gemini CLI for an open-source (Apache 2.0) terminal agent that signs in with Google, AI Studio or Vertex AI. Its plans page lists no USD prices, and unpaid users were moved to Antigravity CLI.
Starting price$8/mo (Go); Free $0 · Not stated (no USD prices)OpenAI Codex · Gemini CLI
Free tierYes, desktop app only · Listed, availability to verifyOpenAI Codex · Gemini CLI
Plans documented6 · 6OpenAI Codex · Gemini CLI
Open sourceCLI, licence not stated · Apache 2.0OpenAI Codex · Gemini CLI
We wrote this from our own profiles of both tools, each checked on 2026-09-29, built from the vendors' official pages; we ran no benchmark, used no third-party tests and took no vendor payments.
Is OpenAI Codex better than Gemini CLI? The short answer
Pick OpenAI Codex if you already pay for ChatGPT (Go is $8/mo, Plus $20/mo) and want one agent across a local CLI, IDE extension, desktop app, web and iOS, with an API-key route for CI. Pick Gemini CLI if you want an Apache 2.0 terminal agent that signs in with a Google account, an AI Studio key or Vertex AI, and you accept that its plans page shows no USD prices and that unpaid-tier and Google One users were moved to Antigravity CLI on June 18, 2026. The Codex CLI is also open source per its README, so licence is not the deciding factor. We ran no benchmark on either tool, so this is a comparison of documented plans and features, not of output quality.
Based on our profiles of both tools, each last checked on September 29, 2026 (vendor pages re-read on October 2, 2026). No benchmark has been run for either tool yet.
OpenAI Codex or Gemini CLI: which to use, by task
If you only want the answer, this is the table. Everything below is the evidence from the two documented profiles.
| You want to | Use | Why |
|---|---|---|
| Ask questions about a large codebase | Either | Gemini CLI lists querying large codebases; Codex lists focused sessions in an open repo. |
| Edit files from the terminal | Either | Both run a CLI against your local repository and propose edits you review. |
| Refactor across several files in your editor | OpenAI Codex | Codex has extensions for VS Code, Cursor and Windsurf; Gemini CLI documents IDE integration without detail. |
| Look something up on the web while coding | Gemini CLI | Gemini CLI documents Google Search grounding and web fetch; our Codex profile does not. |
| Review pull requests automatically | OpenAI Codex | Codex lists automatic code review on connected GitHub repositories, with ChatGPT plans but not API-key use. |
| Start a task and check back from your phone | OpenAI Codex | Codex runs as a cloud agent on the web and iOS (Plus plan listed); Gemini CLI has no mobile app in our profile. |
| Add your own tools through MCP | Gemini CLI | Gemini CLI documents MCP, extensions and Agent Skills; MCP is not described in our Codex profile. |
| Run in CI with an API key | Either | Codex lists API-key use for CI; Gemini CLI accepts an AI Studio key or Vertex AI credentials. |
| Lock down what the agent may touch | Gemini CLI | Gemini CLI docs list sandboxing, trusted folders and a policy engine; Codex sandbox details were not fetched. |
| Budget a fixed monthly cost | OpenAI Codex | Codex publishes USD prices; Gemini CLI's plans page shows none. |
Who should pick which
Pick OpenAI Codex if
- You already have a ChatGPT plan and want Codex usage shared with it.
- You want the agent in VS Code, Cursor or Windsurf as well as the terminal, plus a desktop app and a cloud agent on the web and iOS.
- You want a published price ladder: Free $0, Go $8/mo, Plus $20/mo, Pro from $100/mo.
- You want to run it in CI with an API key and pay API rates.
Pick Gemini CLI if
- You want an Apache 2.0 terminal agent with Google Search grounding and web fetch built in.
- You already use Google AI plans, AI Studio or Vertex AI and want to sign in with them.
- You want MCP, extensions, Agent Skills and Plan Mode to shape the agent around your own tools.
- You can check Google Cloud pricing yourself, because the plans page lists no USD prices.
What OpenAI Codex does better, and what Gemini CLI does better
OpenAI Codex
- Runs in the CLI, VS Code, Cursor, Windsurf, a desktop app, the web and iOS.
- Published USD prices, from a $0 Free plan up to Pro tiers of $100, $200 or $500.
- Automatic code review and Slack through the cloud features on ChatGPT plans.
- Usage shared with the ChatGPT plan you may already pay for.
Gemini CLI
- Open source under Apache 2.0, so you can inspect it.
- Google Search grounding and web fetch as built-in tools.
- MCP support, extensions, Agent Skills and Plan Mode.
- Sign-in with a Google account, an AI Studio key or Vertex AI, with regional data residency on Vertex.
OpenAI Codex vs Gemini CLI pricing: plans and free tiers
| Plan | Tool | Price | Limits |
|---|---|---|---|
| Free (ChatGPT) | OpenAI Codex | $0/mo | Desktop app only listed; usage limits apply |
| Go | OpenAI Codex | $8/mo | Desktop app only listed; usage limits apply |
| Plus | OpenAI Codex | $20/mo | Codex on CLI, IDE, web and iOS; usage limits apply |
| Pro | OpenAI Codex | From $100/mo ($100, $200 or $500 tiers) | Higher usage than Plus; tier-to-usage mapping not confirmed |
| Business | OpenAI Codex | $25/user/mo billed monthly; $20/user/mo billed annually | Usage limits apply; workspace admin features |
| API key | OpenAI Codex | Pay per API pricing | No GitHub code review or Slack |
| Free (Google account) | Gemini CLI | $0/mo | Verify current availability |
| Google AI Pro | Gemini CLI | Not stated | Higher limits than free |
| Google AI Ultra | Gemini CLI | Not stated | Highest limits |
| Google Developer Program | Gemini CLI | Not stated | Higher limits |
| AI Studio API key | Gemini CLI | Pay as you go | Free-tier data may be used to improve products |
| Vertex AI | Gemini CLI | Google Cloud billing | Regional data residency options |
USD as published on each vendor's pricing page, checked Sep 29, 2026. OpenAI Codex pricing in full · Gemini CLI pricing in full
Usage limits: what the vendors state
| OpenAI Codex | Gemini CLI | |
|---|---|---|
| Messages / rate limits | Usage limits apply per plan; the Pro tier-to-usage mapping was not confirmed, and ChatGPT credits can extend usage | Not stated: our profile lists only "higher limits" on paid plans, and README free-tier numbers may be outdated |
| Context / file size | Not stated | Not stated |
| Seats / team | Business is $25 per user monthly or $20 billed annually; Enterprise/Edu is contact sales | Google Developer Program is listed as a team plan; seat limits not stated |
Feature comparison
| Feature | OpenAI Codex | Gemini CLI |
|---|---|---|
| Image generation | Not stated | Not stated |
| Voice | Not stated | Not stated |
| File upload | Works on your local repository (CLI/IDE) or connected GitHub repos in the cloud | Yes: reads local files; images and PDFs listed as inputs |
| Web search | Not stated | Yes: Google Search grounding and web fetch |
| Agents / tools | Cloud agent, code review and Slack integrations | Yes: MCP, extensions, Agent Skills and Plan Mode |
| API | API key billed at API rates; no GitHub code review or Slack | AI Studio API key or Vertex AI |
| Mobile apps | iOS (Codex on the web and iOS, Plus plan listed) | No |
| IDE integration | VS Code, Cursor, Windsurf | Documented, no detail |
Privacy and data training
| OpenAI Codex | Gemini CLI | |
|---|---|---|
| Training on your data | Not confirmed: privacy page returned 404 | Plans page says free-tier data may be used to improve products; AI Studio pay-as-you-go offers privacy |
| Retention | Not confirmed | Not stated |
| Business controls | Business and Enterprise/Edu plans with workspace admin features; sandboxing and agent approvals are listed in the docs but not fetched | Enterprise configuration docs, trusted folders, policy engine; Vertex AI lists Google Cloud terms, SLA and regional data residency |
Taken from each vendor's published policy pages at the time of our check. Policies change; the source links are at the bottom.
Our hands-on benchmark
Starting from a 40-line Python package with 5 failing tests: fix CSV date parsing and a trailing blank line, add totals_by_customer(), and add a --top N CLI flag. Standard library only, tests must not be edited.
Gemini CLI
—not yet run
Switching between OpenAI Codex and Gemini CLI: what carries over
OpenAI Codex → Gemini CLICarries over
- Terminal-first workflow: both start in your repository folder, propose edits and run commands.
- Review-before-commit habit: check the diff and run your own tests.
- Native VS Code, Cursor and Windsurf extensions, the desktop app, and the web and iOS cloud agent.
- Automatic GitHub code review and Slack integrations.
Gemini CLI → OpenAI CodexCarries over
- Terminal-first workflow with file edits and shell commands.
- Project context habits: keep notes for the agent in a project file, as with GEMINI.md.
- Google Search grounding and web fetch as documented built-in tools.
- Gemini CLI's MCP-based extensions, Agent Skills and Plan Mode as documented.
Pros and cons
OpenAI Codex
- Free plan available to try Codex
- Several surfaces: CLI, IDE, app, web
- API-key option for CI
- Usage limits apply per plan
- API-key use lacks cloud features such as GitHub code review and Slack
- Some models retire Oct 14, 2026 (GPT-5.5)
Gemini CLI
- Open source under Apache 2.0
- Multiple auth paths: Google account, API key, Vertex AI
- Extensible via MCP and extensions
- Unpaid tier and Google One users were moved to Antigravity CLI on June 18, 2026
- No USD prices shown on the plans page
- Free-tier API data may be used to improve products
The two tools
OpenAI's coding agent for the CLI, IDE extension, desktop app, web and iOS, included in ChatGPT plans or billed by API.
Free stops at: Desktop app only listed, Usage limits apply
Listed Not yet reviewed
Verified developers.openai.com (opens OpenAI Codex website in a new tab)
Free · paid from $8/mo US · checked Sep 29
Open-source terminal AI agent from Google bringing Gemini to the command line; site notes unpaid and Google One users moved to Antigravity CLI.
Free stops at: Verify current availability
Listed Not yet reviewed
Verified geminicli.com (opens Gemini CLI website in a new tab)
Pricing US price unconfirmed
OpenAI Codex or Gemini CLI: how to choose
- Need a published monthly price today? Codex lists $8/mo on Go and $20/mo on Plus; Gemini CLI lists none.
- Need a free option? Codex has a Free ChatGPT plan; Gemini CLI lists a free Google account plan, but check availability after the Antigravity CLI move.
- Work in VS Code, Cursor or Windsurf, or on iOS? Codex covers them; Gemini CLI documents IDE integration without detail.
- Want built-in web search and MCP extensions? Gemini CLI documents both.
- Want the source code? Gemini CLI is Apache 2.0, and the Codex CLI is open source with its licence not stated in our profile.
- Our pick: Codex if you already pay for ChatGPT; Gemini CLI if you already use Google AI, AI Studio or Vertex AI.
Frequently asked questions
Which is cheaper, OpenAI Codex or Gemini CLI?
We cannot rank them on price. Codex publishes USD prices through ChatGPT: Free $0, Go $8/mo, Plus $20/mo, Pro from $100/mo, Business $25 per user monthly or $20 billed annually. The Gemini CLI plans page shows no USD prices for Google AI Pro, Google AI Ultra or the Developer Program, so a monthly figure needs a Google quote or Google Cloud pricing.
Do Codex and Gemini CLI have a free option?
Codex does: a Free ChatGPT plan includes it, though Free and Go list the desktop app only. Gemini CLI lists a Free (Google account) plan, but the site says unpaid-tier and Google One users were moved to Antigravity CLI on June 18, 2026, so check what you can still use.
Can I use Codex or Gemini CLI with just an API key?
Yes for both. Codex with an API key is billed at API rates and lacks cloud features such as GitHub code review and Slack. Gemini CLI accepts an AI Studio key (pay as you go) or Vertex AI credentials; free-tier API data may be used to improve Google products.
Is Codex or Gemini CLI open source?
Gemini CLI is open source under Apache 2.0, per its README. The Codex CLI is described as open source and lives in the openai/codex repository, but our profile does not state its licence.
Which has better privacy terms, Codex or Gemini CLI?
Neither is fully confirmed. Our Codex profile has no training or retention terms because its privacy page returned 404. For Gemini CLI, the plans page says free-tier data may be used to improve products, and Vertex AI lists Google Cloud terms and regional data residency. Retention is not stated for either.
Why choose Codex over Gemini CLI?
Codex reaches more places: CLI, VS Code, Cursor, Windsurf, a desktop app, the web and iOS, with usage shared with your ChatGPT plan and published USD prices from $8/mo. Gemini CLI is the pick for Google sign-in, Search grounding and MCP extensions.
Sources
- https://developers.openai.com/codex/
- https://developers.openai.com/codex/pricing
- https://developers.openai.com/codex/cli
- https://raw.githubusercontent.com/openai/codex/main/README.md
- https://learn.chatgpt.com/docs
- https://geminicli.com/
- https://geminicli.com/plans/
- https://geminicli.com/docs/
- https://raw.githubusercontent.com/google-gemini/gemini-cli/main/README.md
Only official vendor pages. No third-party benchmarks, forum threads or press were used. How we review.