GPT-5.3-Codex-Spark creates a separate real-time coding tier
OpenAI released a 128k, text-only research preview of GPT-5.3-Codex-Spark for low-latency coding in Codex. Served on Cerebras Wafer Scale Engine 3, it was reported at more than 1,000 tokens per second and was available to ChatGPT Pro users with limited API design-partner access.
Why it matters: Interactive editing and long-running autonomous work are separating into different serving paths, models and hardware rather than forcing one model to optimize for both.