OpenAI kills its dedicated coding model Codex again, folding it into GPT-5.5

With GPT-5.4, OpenAI rolled its separate Codex model for programming tasks into the main model. There's no dedicated coding line anymore, explains Romain Huet, OpenAI's Head of Developer Experience. That makes 5.3, which shipped in early February, the last standalone Codex model. Huet says GPT-5.5 brings big gains in agentic coding—where AI handles programming tasks on its own—plus better computer use and stronger performance on general tasks.

GPT-5.5 also uses fewer tokens than GPT-5.4 on the same Codex tasks, meaning better results with lower resource use, Huet says. That said, even with lower token usage factored in, API pricing still goes up about 20 percent.

For anyone following OpenAI's history, this is familiar territory. The company originally had a Codex code model, which it shut down in 2023 in favor of general-purpose language models. Codex made a comeback in May 2025 as Codex-1, based on o3, paired with the Codex AI agent software. That software is still being developed and remains a key focus for OpenAI alongside ChatGPT.