OpenAI: GPT-5.1-Codex

deprecatedproprietary

GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows.

Intelligence
Reasoning
Speed
Context
400K
Max output
128K
Input price
$1.25/1M tokens
Output price
$10/1M tokens

Capabilities

Reasoning & Interaction
Reasoning
Tool Calling
Output Control
Structured Output
JSON Mode
Infrastructure
Streaming

Details

Model IDopenai/gpt-5.1-codex
Provider OpenRouter
Creator OpenAI
Familygpt-5.1
Licenseproprietary
Statusdeprecated
Typechat
Input modalitiestext, image
Output modalitiestext
Open weightNo
Parameters—
Architecture—
Context window400K tokens
Max input—
Max output128K tokens
Reasoning tokensYes
Knowledge cutoff
Release date
Deprecation date
Sourceofficial

Tools

Function Callingfunction_calling
Call external functions and APIs

Pricing

Input
$1.25
Output
$10
Cache write
—
Cache read
$0.13
Batch in
—
Batch out
—

Family Comparison: gpt-5.1

ModelContextMax outPricing
OpenAI: GPT-5.1-Codex-Mini400K128K$0.25$2
OpenAI: GPT-5.1 (batch)400K128K$0.63$5
OpenAI: GPT-5.1 Chat128K32K$1.25$10
OpenAI: GPT-5.1-Codex-Max400K128K$1.25$10
OpenAI: GPT-5.1-Codex400K128K$1.25$10
OpenAI: GPT-5.1400K128K$1.25$10

API

GET/v1/models/openrouter/openai/gpt-5.1-codex

OpenAI: GPT-5.1-Codex

deprecated
openai/gpt-5.1-codex

GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows.

Changes · 7 entries
openai/gpt-5.1-codexupdateca7a400Nov 2, 2026, 03:02 AM
pricingcached input$0.125→$0.13
openai/gpt-5.1-codexupdatedbe2d73Jul 31, 2026, 06:07 AM
pricingcached input$0.125→$0.13
openai/gpt-5.1-codexupdate20c73acJul 17, 2026, 02:34 AM
pricingcached input$0.13→$0.125
openai/gpt-5.1-codexupdatebbc8212May 29, 2026, 12:04 AM
pricingcached input$0.125→$0.13
openai/gpt-5.1-codexupdate1cd659eMar 24, 2026, 04:19 AM
capabilitiesjson modeyes
openai/gpt-5.1-codexupdate2b100acMar 23, 2026, 05:30 AM
model_typechat
release_date2025-11-13
taglineGPT-5.1-Codex is a specialized version of GPT-5.1 optimiz...
tools["function_calling"]
openai/gpt-5.1-codexcreate7f5c66fMar 21, 2026, 05:16 AM