on monday, OpenAI launches CodexAn agentive coding tool marketed to software developers. Today, OpenAI also launched a new model designed to turbo-charge codecs: GPT-5.3 codec.
The company says the model transforms Codex from an agent that can only “write and review code” to one that “developers and professionals can do almost anything on computers, expanding who can create software and how work is done.” After testing its new model against several performance benchmarks, OpenAI claims it can “build highly functional complex games and apps in just a few days.”
OpenAI says the GPT-5.3 codec is also 25 percent faster than its previous model (GPT-5.2) and that it was the first model the company “played a key role in building itself,” meaning that company employees used early versions of the program themselves to debug and evaluate how it was performing.
The new model release is especially hot on the heels of a New Agentic Coding Model Released by its competitor Anthropic. In fact, OpenAI and Anthropic originally planned to release their two agentive coding tools at exactly the same time: 10 a.m. PST. However, shortly before the original release time, Anthropic moved up its release date by 15 minutes, leaving OpenAI slightly better off in the race to promote the models.
