OpenAI Launches GPT-5.5 Instant Globally to All Free Users on June 26

OpenAI launched GPT-5.5 Instant, its latest model version, to free users globally starting June 26, according to an official announcement. The model replaces the previous GPT-5.3 Instant as the default across all ChatGPT platforms, serving hundreds of millions of active users.

The updated model shows significant performance gains across medical, legal, and financial domains, with hallucination rates substantially reduced and benchmark scores approaching the flagship model from two years ago. GPT-5.5 Instant features optimized output formatting, intelligent routing for adaptive reasoning, and context windows ranging from 16K to 128K tokens based on user tier.