OpenAI: GPT-5.3-Codex
Analysis Summary
OpenAI's GPT-5.3-Codex is a coding-oriented model with strong reasoning signals and a 400K context window. It supports vision and file input, tool use, and function calling, allowing it to work across repositories, technical documents, screenshots, and connected development systems. The combination is suited to workflows that require both implementation and interpretation of surrounding project context.
It fits code generation, debugging, repository analysis, technical documentation, and engineering agents with controlled access to tools. Strong long-context and terminal-related results support practical development work, although the supplied record does not include a dedicated coding index, so teams should validate performance against their own repositories and test suites. It is less naturally positioned for broad creative content than a general flagship.
Pricing is premium, especially for output. Adopt it where engineering productivity and tool integration justify the cost, with a cheaper model for routine coding explanations and documentation.
Assessed August 9, 2026
Editorial notes
GPT-5.3-Codex delivers strong reasoning, coding-oriented workflow support, a 400K context, vision, and tool calling, making it well suited to software engineering and complex technical agents at premium output cost.
Rankings consider pricing, capabilities, benchmarks, and real-world applicability and are refreshed as new models launch. Feedback?
DFO Verdict
GPT-5.3-Codex delivers strong reasoning, coding-oriented workflow support, a 400K context, vision, and tool calling, making it well suited to software engineering and complex technical agents at premium output cost.
Benchmark scores
Magenta = intelligence · Ink = technical/agentic · Cyan = content & long-context · Grey = community benchmarks. Data: Artificial Analysis, Hugging Face.
45.5 Intelligence Index
How OpenAI: GPT-5.3-Codex compares
OpenAI: GPT-5.3-Codex ranks #34 of 420 AI models we track for overall intelligence. Its 400K-token context window is larger than 78% of the models we list. At $1.75 per million input tokens it is cheaper than 19% 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 | $1.75 | $0.001750 |
| Output | $14.00 | $0.014000 |
What would OpenAI: GPT-5.3-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 688 models → Price Calculator
These numbers get smaller with the right architecture.
We route routine calls to cheap models and save OpenAI: GPT-5.3-Codex for the hard ones. Most clients cut their estimate by 60-80%.
Talk to our teamAbout OpenAI: GPT-5.3-Codex
GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, combining the frontier software engineering performance of GPT-5.2-Codex with the broader reasoning and professional knowledge capabilities of GPT-5.2. It achieves state-of-the-art results..
Frequently asked questions about OpenAI: GPT-5.3-Codex
How much does OpenAI: GPT-5.3-Codex cost?
OpenAI: GPT-5.3-Codex costs $1.75 per million input tokens and $14.00 per million output tokens.
What is the context window of OpenAI: GPT-5.3-Codex?
OpenAI: GPT-5.3-Codex has a context window of 400,000 tokens (400K).
What can OpenAI: GPT-5.3-Codex do?
OpenAI: GPT-5.3-Codex supports image/vision input, tool use, and function calling.
Who created OpenAI: GPT-5.3-Codex?
OpenAI: GPT-5.3-Codex is developed by OpenAI and was released on February 24, 2026.
