GPT-5.5 Instant
2026-05-05 · Publisher : OpenAI · Domain : Artificial Intelligence
OpenAI replaces GPT-5.3 Instant with GPT-5.5 Instant as ChatGPT's default model, with 52.5% fewer hallucinated claims on high-stakes topics.
What changes
- Clearer, more concise answers, better tailored to the user.
- Richer personalization based on past conversations, files and Gmail (gradual rollout).
- Memory sources visible to ChatGPT users.
- GPT-5.3 Instant remains available for three months to paid subscribers before being retired.
### Specifications - Availability: all ChatGPT users; API via the chat-latest alias. - Context, maximum output and knowledge cutoff: not disclosed in the pages read. - OpenAI recommends GPT-5.5 rather than chat-latest for production use in the API. - API identifier: chat-latest. ### Pricing | Input | Cached input | Output | | --- | --- | --- | | $5.00 | $0.50 | $30.00 | Price per million tokens (USD) of the chat-latest alias, current pricing page. Pricing not disclosed in the post. ### Benchmarks | Internal measure | Result vs GPT-5.3 Instant | | --- | --- | | Hallucinated claims, high-stakes prompts (medicine, law, finance) | -52.5% | | Inaccurate claims, conversations flagged by users | -37.3% | Scores published by the vendor. Internal evaluations. ### Key takeaways ChatGPT's default model gains mainly in factual reliability. For production in the API, OpenAI steers toward GPT-5.5 rather than the chat-latest alias.
Links
Tags : LLM, OpenAI, GPT-5, Instant, ChatGPT