GPT-5 Codex
by OpenAI
GPT-5-Codex is a specialized version of GPT-5 optimized for software engineering and coding workflows. It is designed for both interactive development sessions and long, independent execution of complex engineering tasks. The model supports building projects from scratch, feature development, debugging, large-scale refactoring, and code review. Compared to GPT-5, Codex is more steerable, adheres closely to developer instructions, and produces cleaner, higher-quality code outputs. Reasoning effort can be adjusted with the `reasoning.effort` parameter. It adapts reasoning effort dynamically—providing fast responses for small tasks while sustaining extended multi-hour runs for large projects. The model is trained to perform structured code reviews, catching critical flaws by reasoning over dependencies and validating behavior against tests. It also supports multimodal inputs such as images or screenshots for UI development and integrates tool use for search, dependency installation, and environment setup. Codex is intended specifically for agentic coding applications.
Specifications
Technical details and pricing.
Benchmarks
10 benchmark scores from Artificial Analysis.
Composite Indices
Intelligence, Coding, Math
Standard Benchmarks
Academic and industry benchmarks
Frequently Asked Questions
What is GPT-5 Codex good for?
Use GPT-5 Codex for everyday tasks like writing, summarizing, brainstorming, and getting clear explanations.
How much does GPT-5 Codex cost?
Pricing is based on usage. Current rates are $1.25/1M tokens for input and $10.00/1M tokens for output.
Can I try GPT-5 Codex for free?
Yes. You can start a chat instantly and test the model before deciding on a plan.
Does GPT-5 Codex support images or audio?
GPT-5 Codex can understand images.
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Benchmarks and pricing are sourced from Artificial Analysis where available. OpenRouter specs are used as a fallback.