GPT 5.3 Codex is an AI model by OpenAI designed to assist with coding and software development. It is an evolution of previous Codex models, improving upon both coding performance and reasoning capabilities. GPT 5.3 Codex is designed for agent-style development workflows, where it can utilize tools, operate computers, and complete longer tasks from beginning to end. OpenAI describes it as more of an interactive partner than a simple tool.
Key features of GPT 5.3 Codex include faster performance (reported as 25% faster than previous versions), enhanced agentic capabilities for handling complex tasks, and real-time steering, which allows users to guide the model while it's working. It also demonstrates stronger performance on coding and computer-use benchmarks and is classified as "high capability" for cybersecurity tasks. It is available to paid ChatGPT subscribers via the Codex app, CLI, and IDE extensions. While specific API pricing for GPT 5.3 Codex hasn't been released, it is accessible through paid ChatGPT plans, such as Plus, Pro, Business, or Enterprise, with the cost varying by tier, starting at $20 per month for ChatGPT Plus. A research preview of GPT 5.3 Codex-Spark, a smaller, faster version of the model, is available for Pro users.
