GPT-5.1-Codex-Max vs GPT-5.3 Chat
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for GPT-5.1-Codex-Max and GPT-5.3 Chat.
GPT-5.1-Codex-Max
GPT-5.1-Codex-Max is OpenAI’s latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic...
GPT-5.3 Chat
GPT-5.3 Chat is an update to ChatGPT's most-used model that makes everyday conversations smoother, more useful, and more directly helpful. It delivers more accurate answers with better contextualization and significantly...
Technical Specifications
| Specification | GPT-5.1-Codex-Max | GPT-5.3 Chat |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Context Window | 400,000 tokens | 128,000 tokens |
| Agent Suitability | N/A | N/A |
| Time to First Token (TTFT) | N/A | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2025-12-04 | 2026-03-03 |
API Pricing Comparison
Input Price per Million Tokens
GPT-5.1-Codex-Max
$1.25
GPT-5.3 Chat
$1.75
Output Price per Million Tokens
GPT-5.1-Codex-Max
$10.00
GPT-5.3 Chat
$14.00
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
GPT-5.1-Codex-Max Quirks & Gotchas
No developer gotchas reported.
GPT-5.3 Chat Quirks & Gotchas
No developer gotchas reported.