OpenAI has introduced GPT-4.1, a successor to the GPT-4o multimodal artificial intelligence model launched by the company last year. During a livestream on Monday, OpenAI said GPT-4.1 is better than GPT-4o “on just about every dimension.”

Two smaller model versions are also included in this rollout: a lightweight GPT-4.1 Mini model that, like its predecessor, is more affordable for developers to tinker with, and GPT-4.1 Nano, which OpenAI says is “our smallest, fastest, and cheapest model ever.”

The launch comes as OpenAI plans to phase out its two-year-old GPT-4 model from ChatGPT on April 30th, announcing in a changelog that recent upgrades to GPT‑4o make it a “natural successor” to replace it. GPT-4o, the current default model in ChatGPT, was updated last month to bring new image-generation capabilities to the chatbot, which proved so popular that OpenAI had to limit requests and put access to free ChatGPT accounts on hold to prevent its GPUs from “melting.”

OpenAI is also set to debut the full version of its o3 reasoning model and an o4 mini reasoning model any day now, with references having already been spotted in the latest ChatGPT web release by AI engineer Tibor Blaho.