GPT-5.3 Codex Delivers Faster Self-Improving Code

OpenAI's GPT-5.3 Codex, described by Paul Solt, is a coding-focused model that adds self-improvement capabilities and integration tools. The model reportedly delivers a 25% speed improvement over GPT-5.2, includes Codex CLI/IDE/app compatibility, and promises upcoming API access, improving debugging, iterative development, and real-world coding tasks. These changes aim to make AI-assisted development faster and more adaptable for professional workflows.