Codex CLI vs Gemini 3.8 Flash

A side-by-side comparison of features, pricing, and characteristics.

Codex CLI

An open-source, terminal-based AI coding agent by OpenAI that automates repository tasks, reviews pull requests, and runs tests in sandboxed environments.

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Gemini 3.8 Flash

Google stable Flash model for long-horizon software engineering and autonomous agents.

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AttributeCodex CLIGemini 3.8 Flash
Pricing typeFree + paid (from $20/mo)Paid
Korean supportNoNo
PlatformsmacOS, Linux, Windows (WSL2)-
Open sourceYesNo
API available-Available
SDK--
LLM-based--
Multimodal--
AI modelGPT, Codex-
GitHub Stars122.0K-
VendorOpenAI-
CategoryDeveloper ToolsDeveloper Tools
DetailsView View

Codex CLI key features

  • Terminal-based execution (CLI)
  • Execution in an isolated cloud sandbox
  • Natural language-based code generation and editing
  • Automated testing and debugging loop
  • Git and GitHub workflow integration (automatic PR generation)
  • Custom skill expansion (SKILL.md)