Introducing GPT‑5.3‑Codex‑Spark

OpenAI announced GPT-5.3-Codex-Spark, a smaller and faster version of their GPT-5.3-Codex model made through a partnership with Cerebras, designed for real-time coding tasks. The model processes text at 1,000 tokens per second (meaning it generates 1,000 words or word pieces per second) with a 128k context window (the amount of text it can consider at once), making it useful for iterative coding work where developers want to stay focused and make rapid changes. While the output quality is lower than the standard GPT-5.3-Codex, the speed enables better productivity for hands-on coding sessions.