OpenAI: GPT-5.1-Codex
Analysis Summary
OpenAI GPT-5.1-Codex is a coding-focused model built for engineering workflows. It supports a 400,000-token context window, vision, tool use, and function calling, allowing teams to connect it to repositories, development tools, and structured automation. Its measured intelligence is strong, although the supplied data does not include the full coding benchmark set used for direct comparison with newer coding flagships.
The model fits code generation, refactoring, repository analysis, debugging, and tool-driven engineering tasks. Large context is particularly useful when changes require understanding multiple files or extended project instructions. It should be paired with tests and review for production changes, and it is not the first choice for nuanced editorial or brand writing.
Its pricing is moderate for a specialist engineering model. Adopt it for coding agents and developer assistance where reliable tool integration matters more than general-purpose versatility.
Assessed August 9, 2026
Editorial notes
GPT-5.1-Codex combines strong reasoning with a 400K context window, vision, tool use, and function calling for software workflows. It is well suited to codebase tasks and engineering agents, while its coding specialisation makes it less natural for broad content work.
Rankings consider pricing, capabilities, benchmarks, and real-world applicability and are refreshed as new models launch. Feedback?
DFO Verdict
GPT-5.1-Codex combines strong reasoning with a 400K context window, vision, tool use, and function calling for software workflows. It is well suited to codebase tasks and engineering agents, while its coding specialisation makes it less natural for broad content work.
How OpenAI: GPT-5.1-Codex compares
OpenAI: GPT-5.1-Codex ranks #95 of 433 AI models we track for overall intelligence. Its 400K-token context window is larger than 76% of the models we list. At $1.25 per million input tokens it is cheaper than 23% of comparable models.
Dark bar = input · light bar = output, scaled to the priciest peer.
1M tokens ≈ 8 full-length novels or ~2,500 pages of business documents in a single request.
Strongest on business fit. The pulled-in technical corner is the trade-off, and if the shape matters more than the price, this is your model.
Compare shapes side-by-side →Pricing
| Token Type | Cost per 1M tokens | Cost per 1K tokens |
|---|---|---|
| Input | $1.25 | $0.001250 |
| Output | $10.00 | $0.010000 |
What would OpenAI: GPT-5.1-Codex cost your business?
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A website chatbot handling around 100 customer conversations a day, a few short messages each.
Full calculator with 748 models → Price Calculator
These numbers get smaller with the right architecture.
We route routine calls to cheap models and save OpenAI: GPT-5.1-Codex for the hard ones. Most clients cut their estimate by 60-80%.
Talk to our teamAbout OpenAI: GPT-5.1-Codex
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..
Frequently asked questions about OpenAI: GPT-5.1-Codex
How much does OpenAI: GPT-5.1-Codex cost?
OpenAI: GPT-5.1-Codex costs $1.25 per million input tokens and $10.00 per million output tokens.
What is the context window of OpenAI: GPT-5.1-Codex?
OpenAI: GPT-5.1-Codex has a context window of 400,000 tokens (400K).
What can OpenAI: GPT-5.1-Codex do?
OpenAI: GPT-5.1-Codex supports image/vision input, tool use, and function calling.
Who created OpenAI: GPT-5.1-Codex?
OpenAI: GPT-5.1-Codex is developed by OpenAI and was released on November 13, 2025.