OpenAI

GPT-6 is three API models, not one. Astra is the flagship. GPT-6.1 Sol is the model most teams should price first. Luna is for volume.

openai.com

GPT-6 Astra

3 Sep 2026 · Closed · OpenAI's flagship. It ties Gemini 4 Argon at 53 on max or high settings and trails Opus 5.5 and Sonnet 5.5 at their peaks. It is token-efficient relative to Claude on measured tasks.

GPT-6.1 Sol

29 Sep 2026 · Closed · Near-Astra intelligence at less than a quarter of Astra's measured task cost. This is the closed model to try first.

GPT-6 Luna

22 Sep 2026 · Closed · The cheap end of GPT-6. Fast, and not a substitute for Sol or Opus.