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GPT-5.1 Codex Max

GPT-5.1-Codex-Max is OpenAI’s latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic workflows spanning software engineering, mathematics, and research. GPT-5.1-Codex-Max delivers faster performance, improved reasoning, and higher token efficiency across the development lifecycle.

openai/gpt-5.1-codex-max
Organization
OpenAI
Family
gpt-codex
Providers
8
Context
400,000
Output limit
128,000
Knowledge
2024-09-30
Release
2025-11-13
Updated
2025-11-13
Weights
Closed
Input
text, image
Output
text
Capabilities
Tools, Reasoning, Structured

Providers

Compare every cataloged offer for this model, including its provider, route, token limits, price, and capabilities.

8 offers · USD per million tokens
ProviderModel IDContextOutputInput / output · 1MReasoningToolsStructuredDetails
Azure
gpt-5.1-codex-max
400,000128,000$1.25 / $10.00YesYesYes
View
Azure Cognitive Services
gpt-5.1-codex-max
400,000128,000$1.25 / $10.00YesYesYes
View
Eden AI
azure/gpt-5.1-codex-max
272,000128,000$1.25 / $10.00YesYesYes
View
Kilo Gateway
openai/gpt-5.1-codex-max
400,000128,000$1.25 / $10.00YesYesYes
View
NanoGPT
openai/gpt-5.1-codex-max
400,000128,000$2.50 / $20.00YesYesYes
View
Ofox
openai/gpt-5.1-codex-max
256,000128,000$1.00 / $8.00YesYesYes
View
Azurevia OpenRouter
openai/gpt-5.1-codex-max
unknown		400,000128,000$1.25 / $10.00YesYesYes
View
Vercel AI Gateway
openai/gpt-5.1-codex-max
400,000128,000$1.25 / $10.00YesYesYes
View

Prices and limits apply to each offer. A dash means the value is not provided. OpenRouter offers show the hosting provider and routing channel separately.

Pricing

Compare token rates and cache charges across available routes and hosting configurations.

USD per million tokens
Input from$1.00Per 1M input tokens
Output from$8.00Per 1M output tokens
Available offers8Across 8 providers

Lowest listed input and output prices across the offers above; they may belong to different providers. These are base rates, before conditional pricing, discounts or additional fees.

Endpoint price comparisonLatest observed snapshot · 1 lowest-priced configuration
InputOutput
Azureazure
$1.25$10.00
openai/gpt-5.1-codex-maxObserved
Input
$1.25
Output
$10.00
Cache read
$0.125
Additional fees and pricing conditions
web search
$0.01 / search
Hosting prices through OpenRouter All endpoints and cache rates
EndpointInput / 1MOutput / 1MCache read / 1MCache write / 1M
Azureazure$1.25$10.00$0.125—

Each row is a hosting configuration. Open an offer in Providers for its full pricing conditions and additional fees. Endpoint observations may differ from the routing catalog's base price.

Performance

Review reported latency and output-throughput percentiles from the latest observed rolling window.

Latest 30-minute observation

Time to first token · milliseconds

Latency distributionRolling 30-minute snapshot · 1 endpoint
P50P75P90P99
Azureazure
3,581.5–24,575.53 ms
All latency percentiles 1 endpoints
EndpointP50P75P90P99
Azureazure3,581.5 ms5,923.5 ms10,419 ms24,575.53 ms

Output throughput · tokens per second

Throughput distributionRolling 30-minute snapshot · 1 endpoint
P50P75P90P99
Azureazure
85–124.14 t/s
All throughput percentiles 1 endpoints
EndpointP50P75P90P99
Azureazure85 t/s92.25 t/s107.6 t/s124.14 t/s

Percentiles describe the observed request distribution. These are snapshots of a rolling window, not a historical time series.

Uptime

Compare successful request rates across the latest 5-minute, 30-minute, and 24-hour observations.

Successful requests by window
Availability by endpointCurrent overlapping windows · 1 endpoint
Endpoint5 minutes30 minutes24 hours
Azureazure

Reported by OpenRouter at the time of collection; rate-limited requests are excluded. A dash means no measurement was reported. This is not a live availability check.

Technical details & API

Explore specifications, supported parameters, reasoning controls, and API identifiers for each OpenRouter route.

Current route specifications
openai/gpt-5.1-codex-maxObserved
Context
400,000
Maximum output
128,000
Tokenizer
GPT
Input
text, image
Output
text
Moderation
No
Added to OpenRouter
2025-12-04
Base URLhttps://openrouter.ai/api/v1
Model IDopenai/gpt-5.1-codex-max
Version IDopenai/gpt-5.1-codex-max-20251204

Reasoning

Required
Yes
Enabled by default
Not reported
Default effort
medium
Supported efforts
xhigh, high, medium, low

Supported parameters

  • include_reasoning
  • max_completion_tokens
  • reasoning
  • reasoning_effort
  • response_format
  • seed
  • structured_outputs
  • tool_choice
  • tools
  • verbosity

Frequently asked questions

Answers based on the model metadata and serving offers currently in the catalog.

How much does GPT-5.1 Codex Max cost?

Listed rates start at $1.00 per million input tokens and $8.00 per million output tokens. Prices vary by provider and configuration; see Pricing for details.

Which providers offer GPT-5.1 Codex Max?

There are 8 cataloged offers across 8 providers. Compare model IDs, prices and limits in Providers.

What is the context window?

The cataloged model context is 400,000 tokens. Each serving endpoint may apply a different limit.

Does it support tools and structured output?

Tool calling: Yes. Structured output: Yes. Support can vary by endpoint.

Catalog history · 2 recorded revisions

Metadata observations since this model was first cataloged. These are not model release versions.

  • · d590f607a203
  • · 962a46e67261