OpenAI has officially released its latest-generation large language model, GPT-5.5. According to reports, the new model is smarter and requires significantly fewer tokens to complete the same Codex tasks, which will offset some of the cost pressure from the increased unit price in practical use. GPT-5.5 is already available to all paid users of ChatGPT Plus, Pro, Business, and Enterprise. The API version is coming soon. The API side supports an extremely wide context window of up to 1 million tokens, while the Codex subscription plan offers a window of 400,000 tokens.