GPT‑5.3‑Codex‑Spark – Ultra-fast real-time coding model with extended context

Summary: GPT‑5.3‑Codex‑Spark delivers 15x faster code generation with a 128k token context window, enabling real-time collaboration and rapid iteration. It prioritizes low latency and minimal edits, requiring user prompts to run tests.

What it does

It generates code interactively with near-instant responses, allowing users to interrupt or redirect its output. The model focuses on targeted edits without automatic test execution.

Who it's for

Designed for developers needing fast, efficient coding assistance during interactive sessions.

Why it matters

It reduces latency in coding workflows, enabling quicker fixes and iterations without excessive computational cost.