GPT-5.3-CODEX
OpenAI's GPT-5.3-CODEX is a chat model exceling at code-related tasks, including completion, generation, and review, as well as reasoning and function calling. Its notable technical trait is a large context window of 272,000 tokens, allowing it to process extensive inputs.
Input
Output
Context
272K
Max Output
128K
Parameters
-
Technical Specifications
Model TypeCode
Context Window272,000 tokens
Max Output Tokens128,000 tokens
ParametersNot available
Release DateFeb 8, 2026
Training CutoffAug 31, 2025
Licenseproprietary
Open SourceNo
Input Modalities
ImageText
Output Modalities
Text
Capabilities
Benchmarks
Artificial Analysis
42.5%
HLE
78.3%
AA-LCR
91.5%
GPQA
86.0%
Tau2-Bench
75.4%
IFBench
53.2%
SciCode
45.5
Intelligence
53.0%
Terminal-Bench Hard
126
Speed (tok/s)
40.1
TTFA (s)
40.1
TTFT (s)
Resources & Links
proprietary, Proprietary - API access only
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Data sourced from official provider APIs and documentation
Last updated: Aug 28, 2026
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