OpenAI released GPT-5.3-Codex-Spark to ChatGPT Pro subscribers through the Codex app, command-line, and VS Code extension.

This smaller, speed-focused version of GPT-5.3-Codex generates over 1,000 tokens per second—up to 15 times faster on coding benchmarks—thanks to Cerebras' Wafer Scale Engine 3 chip. The tool aims to act as a seamless pair programmer, with plans for broader rollouts and multimodal features ahead.