GPT- 5.3-Codex-Spark Research Preview with 1000 Tokens per Second

An ultra-fast model for real-time coding rolling out today to ChatGPT Pro users in the Codex app, CLI, and IDE extension. From the announcement: > Codex-Spark marks the first milestone in our partnership with Cerebras, which we announced in January⁠. Codex-Spark is optimized to feel near-instant when served on ultra-low latency hardware—delivering more than 1000 tokens per second while remaining highly capable for real-world coding tasks. > At launch, Codex-Spark has a 128k context window and is text-only. During the research preview, Codex-Spark will have its own rate limits and usage will not count towards standard rate limits. However, when demand is high, you may see limited access or temporary queuing as we balance reliability across users. You can just build things!