GPT-5.3 Codex
OpenAI's code-specialized model built for agentic software engineering.
GPT-5.
Provider: OpenAI
Strengths
- Code Generation
- Software Engineering
- Debugging
- Architecture
- Agentic Coding
Specifications
- contextWindow: 512,000 tokens
- maxOutput: 64,000 tokens
- training: January 2026 cutoff
- modality: Text, Code
- pricing: Developer tier / Codex subscription