LLM Reference

GPT-5.1 Codex Max

Released
2025-11-19
Last refreshed
2026-06-29
Status
Researched 43d ago
ProprietaryCommercial use: conditionalMultimodalCodingAgentsVisionJSON / Tool use

GPT-5.1 Codex Max is worth evaluating for coding, agents, and vision when its provider route and context window match the workload.

Use it for

  • Teams evaluating coding, agents, and vision
  • Buyers comparing 1 tracked provider route

Do not use it for

  • Workloads where another current model has stronger sourced task evidence
Specifications
Family
GPT-5.1
Released
2025-11-19
Knowledge cutoff
2024-09
Specialization
code
Openness
Proprietary
License
ProprietaryCommercial use: conditional
Weights
Not released
Code
Unknown
Created by

Cutting-edge research and development.

San Francisco, California, United States
Founded 2015
Website
Pricing
Output / 1M
$10.00
Input / 1M
$1.25

Cheapest of 1 route · Vercel AI Gateway · cache read $0.125

About

OpenAI's GPT-5.1-Codex-Max is a code-specialized model released November 19, 2025, optimized for agentic coding tasks including project-scale refactors, debugging, and multi-file edits. Uses context compaction to handle long-running tasks beyond a single context window. 30% more token-efficient than previous Codex on SWE-bench. Supports an extra-high reasoning effort option.

GPT-5.1 Codex Max is a proprietary model in the GPT-5.1 family. The structured metadata tracks multimodal input, reasoning, function calling, tool use, and structured outputs. This page tracks provider routes through Vercel AI Gateway, with the cheapest tracked route listed at $1.25 input and $10 output per 1M tokens. No headline benchmark score is tracked for GPT-5.1 Codex Max yet.

Top use-case fit: coding, agents, and build tasks

Coding

Included by capability and metadata signals in the decision map.

Agents

Included by capability and metadata signals in the decision map.

Vision

Included by capability and metadata signals in the decision map.

Provider price ladder

Compare API pricing across 1 providers for input and output tokens, batch, and cached reads when available.

ProviderInput / 1MOutput / 1MCacheRoute
Vercel AI Gateway$1.25$10.00read $0.125
Serverless

Capabilities

VisionMultimodalReasoningFunction CallingTool UseStructured Outputs

Benchmark peer barsfor Coding

No task-mapped benchmark peers are available for this model yet.

Migration checks

No linked migration route is available for this model yet.

Compare GPT-5.1 Codex Max with other models

Frequently asked questions

How much does GPT-5.1 Codex Max cost?

GPT-5.1 Codex Max is available at $1.25/1M input tokens through Vercel AI Gateway.

When was GPT-5.1 Codex Max released?

GPT-5.1 Codex Max was released on 2025-11-19.

Which providers offer GPT-5.1 Codex Max?

GPT-5.1 Codex Max is available from 1 provider: Vercel AI Gateway.