GPT-5.1-Codex

GPT-5.1-Codex

Developer	OpenAI
Release date	November 13, 2025
Family	GPT
Generation	GPT-5.1
Level
Context window	400K tokens
Max output	128K tokens
Input	Text, image
Output	Text
Knowledge cutoff	2024-09-30
Weights	Closed
Predecessor	GPT-5-Codex
Successor	GPT-5.2-Codex
Website	openai.com
Links	Docs

Part of a series on

OpenAI

No longer available

The publisher shut this model down on July 23, 2026. It can no longer be used from its own API. Recommended replacement: gpt-5.6-sol. Publisher notice

input: $1.25
cached: $0.13
output: $10.00
Context: 400Ktokens
Released: 12mo ago

Specifications

Model

Developer: OpenAI
Family: GPT GPT-5.1
Type: Language model
Released: November 13, 2025
Model ID: openai/gpt-5.1-codex

Capabilities

Input → output: Text, image → Text
Max output: 128K tokens
Tokenizer: GPT
Knowledge cutoff: 2024-09-30

Weights

Openness: Closed

Sources:models.devOpenRouter

Metadata synced Nov 7, 2026, 8:58 AM UTC