Model Releases
GPT-5.5 may not be in the official OpenAI API... but it's available via the apparently approved-of Codex API backdoor So I used that to make…
GPT-5.5 may not be in the official OpenAI API... but it's available via the apparently approved-of Codex API backdoor So I used that to make these pelicans (default and xhigh)! https://simonwillison.n
GPT-5.5 may not be in the official OpenAI API... but it's available via the apparently approved-of Codex API backdoor So I used that to make these pelicans (default and xhigh)! https://simonwillison.net/2026/Apr/23/gpt-5-5/ @bygregorr We want people to be able to use Codex, and their ChatGPT subscription, wherever they like! That means in the app, in the terminal, but also in JetBrains, Xcode, OpenCode, Pi, and now Claude Code. That’s why Codex CLI and Codex app server are open source too! 🙂
Source: Simon Willison (X) | 2026-04-23