GPT-5.1

GPT-5.1 is a family of large language models by OpenAI released in November 2025, succeeding GPT-5. GPT-5.1 Instant and GPT-5.1 Thinking were added to ChatGPT on November 12, 2025 and the API the following day.12

Legacy

GPT-5.1 was succeeded by GPT-5.2 in December 2025.

On April 22, 2026, OpenAI announced these models would be retired from the API on July 23, 2026:

In April 29, 2026, OpenAI reported that the goblin incursion began with GPT-5.1.3

Further reading

Footnotes

  1. GPT-5.1: A smarter, more conversational ChatGPT (OpenAI, Nov 12, 2025) ↩

  2. Introducing GPT-5.1 for developers (OpenAI, Nov 13, 2025) ↩

  3. Where the goblins came from (OpenAI, Apr 29, 2026) ↩

Models

GPT-5.1-Codex-Max2025-11-19Deprecated400K$1.75 / $14
GPT-5.1 Thinking2025-11-12Active400K$1.25 / $10
GPT-5.1 Instant2025-11-12Deprecated128K$1.25 / $10
Polaris Alpha2025-11-06Active400K$1.25 / $10
4 of 4 models