GPT-5.1-Codex

Name: OpenAI GPT-5.1-Codex
Price: 1.25 USD
Availability: InStock
Author: OpenAI

openai/gpt-5.1-codex

GPT-5.1-Codex is a version of OpenAI's GPT-5.1 optimized for agentic coding in Codex and similar environments, released in November 2025 with text and image input and text output. It targets autonomous, long-running software engineering work inside coding agents and tools, and OpenAI notes its underlying snapshot is updated over time. Pick it over general GPT-5.1 when building coding agents; OpenAI serves it through the Responses API only.

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Input price: $1.25USD / 1M tokens
Output price: $10.00USD / 1M tokens
Context window: 400K
Max output: 128K

Production route

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Image URL or upload

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400K context128K max outputVision

Input$1.25/MOutput$10.00/MCache read$0.13/M

OutputReady

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Model card

Specifications

Pricing

Input: $1.25 / 1M tokens
Output: $10 / 1M tokens
Cache read: $0.13 / 1M tokens

Context & modalities

Context window: 400,000 tokens
Max output: 128,000 tokens
Input: Text, image
Output: Text

Capabilities

Chat: Supported
Vision: Supported
Reasoning: Supported
Structured output: Supported
Function calling: Supported
Audio input: Not supported

Access

Provider: OpenAI
Model ID: openai/gpt-5.1-codex
Execution: sync
Base URL: https://api.sandbase.ai
API: Responses API
Endpoint: /v1/responses
API: Chat Completions API
Endpoint: /v1/chat/completions

Start building

Send your first request

Choose either supported API with unified authentication and usage tracking.

Production API

Responses API endpoint

https://api.sandbase.ai/v1/responses

Model ID

openai/gpt-5.1-codex

# The quoted heredoc keeps Unicode and shell metacharacters unchanged.
result=$(curl --fail-with-body --silent \
  -X POST "https://api.sandbase.ai/v1/responses" \
  -H "Authorization: Bearer $SANDBASE_API_KEY" \
  -H "Content-Type: application/json" \
  --data-binary @- <<'SANDBASE_JSON'
{
  "model": "openai/gpt-5.1-codex",
  "input": "Hello",
  "max_output_tokens": 2048
}
SANDBASE_JSON
)
printf '%s\n' "$result"

Choose your model

Compare models

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Model	Context	Input / 1M	Output / 1M	Released
GPT-5.1-CodexThis model `OpenAI`	390.6K	$1.25	$10.00	Nov 13, 2025
GPT-6.1 Terra Pro `OpenAI`	1.1M	$1.00	$5.00	Oct 26, 2026
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GPT-6 Luna Pro `OpenAI`	1.1M	$0.10	$0.50	Sep 22, 2026

Questions

FAQ

How do I call OpenAI GPT-5.1-Codex through SandBase?

Create a SandBase API key, then send requests with the model ID "openai/gpt-5.1-codex" to Responses API (/v1/responses) or Chat Completions API (/v1/chat/completions) at https://api.sandbase.ai. The request examples on this page show the exact payload.

How much does OpenAI GPT-5.1-Codex cost?

$1.25 per 1M input tokens and $10 per 1M output tokens, billed per request from your SandBase balance. Discounts, when available, are shown in the pricing on this page.

What is the context window of OpenAI GPT-5.1-Codex?

400K tokens of context, with up to 128K output tokens per response.

Which features does OpenAI GPT-5.1-Codex support?

OpenAI GPT-5.1-Codex supports vision (image input), reasoning, function calling, structured output. See Specifications above for the full list.

Do I need a separate OpenAI account?

No. One SandBase API key and balance gives you access to OpenAI GPT-5.1-Codex and the other models in the catalog; you do not need to sign up with OpenAI separately.