A pelican for GPT-5.5 via the semi-official Codex backdoor API
Although OpenAI's latest model GPT-5.5 hasn't officially launched its API, developers are already accessing it through a 'semi-official backdoor' in its Codex CLI using their ChatGPT subscription, revealing new dynamics in the battle over AI model distribution channels.
Simon Willison · Apr 24, 2026
Headless everything for personal AI
Personal AI agents are driving services to become 'headless', where APIs replace GUIs as the primary interface, potentially disrupting SaaS pricing and product logic.
Simon Willison · Apr 20, 2026
research-llm-apis 2026-04-04
Simon Willison used AI to analyze raw HTTP APIs from Anthropic, OpenAI, Gemini, and Mistral to redesign LLM library's abstraction layer.
Simon Willison · Apr 5, 2026