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OpenAIProprietary
GPT-5.3
GPT-5.3 is a foundation model developed by OpenAI. It supports a long context window of 1M and is equipped with advanced processing capabilities.
Parameters
Undisclosed
Context Window
1M
License
Proprietary
Release Date
2026-02-20
API Pricing
API pricing for this model is not yet available
Strengths
- ・1 million token long-context understanding
- ・High-performance foundation design by OpenAI
- ・Efficient large-scale data processing
Weaknesses
- ・Opacity due to closed source
- ・Low flexibility due to licensing restrictions
- ・No external access to model internals
Use Cases
- ・Ultra-long document analysis
- ・Understanding large codebases
- ・Maintaining complex contexts
Deep Analysis
Release Date
March 3, 2026
Context Window
128K tokens
Pricing
$1.75 / $14.00 per 1M tokens
Hallucination Reduction
-26.8%
Strengths
- ・Significantly reduced hallucinations
- ・Same pricing as GPT-5.2
- ・Improved conversational quality
Weaknesses
- ・Context reduced to 128K from 400K
- ・No standard benchmarks published
- ・Superseded by GPT-5.4 in 2 days
GPT-5.3 is a conversational quality update focused on reducing hallucinations.
Sources
Analysis generated: 2026-05-24