OpenAI: GPT-5.1-Codex
Analysis Summary
OpenAI's GPT-5.1-Codex is a coding-focused multimodal model with a 400K context window, vision, tool use, and function calling. Its available intelligence result and product design support substantial codebase work, visual development tasks, and tool-driven engineering workflows over very large inputs.
The model is well suited to repository understanding, implementation, debugging, code review, and autonomous software agents. The record does not include a coding index or detailed coding benchmark results, so its comparative engineering reliability should be validated directly. Premium output pricing also argues for routing routine edits and low-risk generation to a cheaper model.
Use it for high-value engineering tasks where long context and integrated tools reduce operational friction. Treat it as a specialist coding deployment until broader benchmark evidence is available.
Assessed September 7, 2026
Editorial notes
GPT-5.1-Codex combines a 400K context, vision, tool use, and function calling with a coding-focused profile. Its premium pricing makes it best suited to high-value engineering and agent workflows rather than routine generation.
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DFO Verdict
GPT-5.1-Codex combines a 400K context, vision, tool use, and function calling with a coding-focused profile. Its premium pricing makes it best suited to high-value engineering and agent workflows rather than routine generation.
How OpenAI: GPT-5.1-Codex compares
OpenAI: GPT-5.1-Codex ranks #105 of 438 AI models we track for overall intelligence. Its 400K-token context window is larger than 75% 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 779 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.