Introducing GPT‑5.3‑Codex‑Spark

Simon Willison reports on OpenAI’s new GPT-5.3-Codex-Spark model, highlighting its rapid launch just four weeks after OpenAI’s partnership announcement with Cerebras. This ultra-fast model is designed for real-time coding within Codex, marking the first integration from the Cerebras collaboration.

Source: Simon Willison