INTRODUCING GPT‑5.3‑CODEX‑SPARK

Summary from the TLDR newsletter

GPT‑5.3‑Codex‑Spark is a smaller version of GPT‑5.3‑Codex designed for real-time coding. It is now available as a research preview to ChatGPT Pro users. The model has a 128k context window. It is text only, and during the research preview, the model will have its own rate limits and usage will not count towards standard rate limits. There may be limited access or temporary queuing when demand is high.