GPT-5.1-Codex

GPT-5.1-Codex by OpenAI excels in the Coding category, where it ranks #42 with a composite score of 62/100. GPT-5.1-Codex is a specialized version of GPT-5.1 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-5.1, 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. Read the [docs here](https://openrouter.ai/docs/use-cases/reasoning-tokens#reasoning-effort-level) Codex integrates into developer environments including the CLI, IDE extensions, GitHub, and cloud tasks. 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. It is particularly strong in areas highlighted by its top benchmark performance and adoption metrics, making it suitable for both individual developers and enterprise teams looking for a reliable coding solution.

GPT-5.1-Codex is priced at $1.25 per million input tokens and $10.00 per million output tokens (USD). Contact the provider for volume discounts and enterprise pricing. Pricing is competitive within the coding category and reflects the model's quality-to-cost ratio.

In the Coding category, GPT-5.1-Codex holds rank #42 out of 6 models tracked. Its quality rank is #42 and adoption rank is #42. You can use our comparison tool at /compare to see detailed side-by-side metrics with specific alternatives. Key differentiators include its composite scoring across benchmarks, community sentiment, and real-world adoption rates.

GPT-5.1-Codex has been evaluated across 6 different signals. Its strongest areas include Capabilities (71/100), Context Window (89/100), Output Capacity (85/100). These scores are derived from industry-standard benchmarks, community ratings, and real-world performance metrics. The composite score of 62/100 reflects a weighted combination of all tracked signals.

GPT-5.1-Codex is a paid model, though some providers may offer trial credits or limited free tiers for evaluation. Check OpenAI's website for current free tier availability and promotional offers.