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Model infoModelsSnapshot: 15 Oct 2026

OpenAI / GPT-5.1

GPT-5.1-Codex-Max

OpenAI text generation, reasoning, coding model with developer-documented API access and version information.

Language models (LLMs)
retiredClosed weightsText generationReasoningCodingAgentsVision
Official documentation (opens in a new tab)Reviewed 12 Oct 2026
15 of 19 specification fields collected
Context window400K400,000 tokens
Maximum output128K128,000 tokens
Input / 1M tokens$1.25OpenAI API
Output / 1M tokens$10.00USD · observed 12 Oct 2026

Specifications

Provider-documented facts. “Not collected” means we have not verified that field yet, not that the feature is unsupported.

Context / input limit
400,000 tokensSource for Context / input limit (opens in a new tab)
Maximum output
128,000 tokensSource for Maximum output (opens in a new tab)
Input modalities
Text, ImageSource for Input modalities (opens in a new tab)
Output modalities
TextSource for Output modalities (opens in a new tab)
Reasoning
SupportedSource for Reasoning (opens in a new tab)
Tool calling
SupportedSource for Tool calling (opens in a new tab)
Structured output
SupportedSource for Structured output (opens in a new tab)
Streaming
SupportedSource for Streaming (opens in a new tab)
Batch processing
Not supportedSource for Batch processing (opens in a new tab)
Fine-tuning
Not supportedSource for Fine-tuning (opens in a new tab)
Knowledge cutoff
2024-09-29Source for Knowledge cutoff (opens in a new tab)
Release date
Not collected
Parameters
Not collected
Architecture
Not collected
Languages
Not collected
Supported API routes
v1/responsesSource for Supported API routes (opens in a new tab)
Snapshots and aliases
gpt-5.1-codex-maxSource for Snapshots and aliases (opens in a new tab)

Aliases and pinned IDs listed by the developer. A snapshot date is not automatically the public release date.

Supported tools
function_calling, web_searchSource for Supported tools (opens in a new tab)
Context caching
SupportedSource for Context caching (opens in a new tab)

Documented on at least one recorded endpoint. See Caching for host, lifecycle and billing restrictions.

Access & pricing

Prices belong to an endpoint and billing tier. A provider listing does not guarantee access for every account or region.

OpenAI API

Provider source (opens in a new tab)
API model ID
gpt-5.1-codex-max
Access
Historical API record. The documented shutdown date has passed.
Regions
Not collected
INPUT / 1M TOKENS$1.25
OUTPUT / 1M TOKENS$10.00

Standard text-token rates. Other modalities, tool usage and processing modes are billed separately. Cached input price: $0.125 / 1M tokens (base tier).

USD · observed 12 Oct 2026 · Pricing evidence (opens in a new tab)
Published billing units · original currency · observed 12 Oct 2026
CategoryUsageRateUnit
Text tokensInput1$1.251M tokens
Text tokensCached input1$0.1251M tokens
Text tokensOutput1$10.001M tokens

Rate conditions

  1. Base published rate. Check the model-card pricing conditions and the request modality.
Pricing source (opens in a new tab)

Data & enterprise terms

API data controls and retention depend on endpoint and account configuration; consult the linked provider policy.

Read the service policy (opens in a new tab)

Caching

Caching can reuse earlier input processing. Availability, lifetime and billing depend on the endpoint. A cache hit still generates a new response.

01 / INITIAL INPUTProcess & retain

The system processes eligible input and retains reusable state.

02 / LATER REQUESTCheck available state

Reuse depends on matching input, session state and the cache policy.

03 / CACHE HITReuse & generate

Reusing state can reduce repeated work. Any charges follow the billing rules below.

OpenAI API

gpt-5.1-codex-max
Documented

Historical pricing or model-card evidence. This endpoint is retired.

Support evidence (opens in a new tab)
How it works
Not collected
Minimum reusable input
Not collected
Lifetime & refresh
Not collected
How to enable it
Not collected
Usage fields
Not collected
Billing rules
Not collected
Limits & data boundaries
Not collected

This model is retired on the recorded endpoint. Any retained prices or capability evidence are historical and do not imply current API access.

Cache reads, writes & storage
ChargeApplies toRate / unit
Cache read1Text tokens · Base tier$0.125 / 1M tokensPricing evidence (opens in a new tab)

Rate conditions

  1. Standard text-token rates. Other modalities, tool usage and processing modes are billed separately.

Observed 12 Oct 2026. Write rates and storage fees are different charges; use the billing rules above.

Caching reviewed 12 Oct 2026

What the measurements say

No benchmark observations have been added for this model. We do not turn a vendor description into a performance score.

Latency and throughput depend on the host, request size, reasoning settings and load. There is no measured speed or global usage figure in this record.

The record behind the model

Why it is included

Proprietary OpenAI release in the official hosted-model catalog. Explicit open-weight releases and unresolved routing aliases are excluded.

Classification evidence (opens in a new tab)

Lifecycle dates

Deprecation announced: gpt-5.1-codex-max22 Apr 2026Source (opens in a new tab)
API shutdown: gpt-5.1-codex-max22 Jul 2026Source (opens in a new tab)

Sources reviewed