OpenAI model

GPT-5.1-Codex API

openai/gpt-5.1-codex is an OpenAI catalog entry with a 400000 token context window. It has an input price of $1.25 per 1M tokens and an output price of $10 per 1M tokens. Its latency band is 1000-3000ms.

Read quickstartEstimate cost
OpenAIPlatform curatedCatalog
ThinkingFunction CallingVision
Input price$1.25 / 1M tokens
Output price$10 / 1M tokens
Context length400k tokens
Max output8.2k tokens

What is GPT-5.1-Codex API in NextModel?

openai/gpt-5.1-codex is an OpenAI catalog entry with a 400000 token context window. It has an input price of $1.25 per 1M tokens and an output price of $10 per 1M tokens. Its latency band is 1000-3000ms.

GPT-5.1 Codex via NextModel: 400k-token context; $1.25 / 1M tokens in / $10 / 1M tokens out per 1M tokens. Capabilities: streaming, tool, json.

Best use cases

  • Call it if you need a 400000 token context window with vision input, tool calling, and JSON output.
  • It is listed for long-context, vision, and agent use cases.
  • Use it when you want a model with that context size at this price point.

When not to use

  • Do not call it if first-party CacheSafety Bench results are a required decision input.
  • This exact model has no published CacheSafety row, so no Safe Hit, Bad Hit, or trap rate is stated for it.
  • Do not call it if you need a context size different from 400000 tokens, because that is the only context value in these notes.

OpenAI-compatible code example

request.sh
curl https://api.nextmodel.app/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $NEXTMODEL_API_KEY" \
  -d '{"model":"openai/gpt-5.1-codex","messages":[{"role":"user","content":"Reply with OK."}]}'

Switching models only changes the model field.

Try it in the playground

Similar alternatives

OpenAICatalog

GPT-5.1

GPT-5.1 via NextModel: 400k-token context; $1.25 / 1M tokens in / $10 / 1M tokens out per 1M tokens. Capabilities: streaming, tool, json.

$1.25 / 1M tokensInput$10 / 1M tokensOutput400kContext
Best forimage understanding, multimodal chat
StreamingTool callingJSON modeVision
Platform curatedCurated and maintained in the NextModel catalog
View details
OpenAICatalog

GPT-5.1 Codex Mini

GPT-5.1 Codex Mini via NextModel: 400k-token context; $0.25 / 1M tokens in / $2 / 1M tokens out per 1M tokens. Capabilities: streaming, tool, json.

$0.25 / 1M tokensInput$2 / 1M tokensOutput400kContext
Best forimage understanding, multimodal chat
StreamingTool callingJSON modeVision
Platform curatedCurated and maintained in the NextModel catalog
View details
OpenAICatalog

GPT-4.1

GPT-4.1 via NextModel: 1M-token context; $2 / 1M tokens in / $8 / 1M tokens out per 1M tokens. Capabilities: streaming, tool, json.

$2 / 1M tokensInput$8 / 1M tokensOutput1MContext
Best forimage understanding, multimodal chat
StreamingTool callingJSON modeVision
Platform curatedCurated and maintained in the NextModel catalog
View details

Compare GPT-5.1 Codex

GPT-5.1 Codex vs GPT-5.1GPT-5.1 Codex vs GPT-5.1 Codex MiniGPT-5.1 Codex vs GPT-4.1GPT-5.1 Codex vs GPT-4.1 MiniGPT-5.1 Codex vs GPT-4.1 Nano

Reading

Articles that explain GPT-5.1 Codex

FAQ

GPT-5.1 Codex API questions

What model id do I send for GPT-5.1-Codex?

Send openai/gpt-5.1-codex to https://api.nextmodel.app/v1 with your OpenAI SDK. If that id is missing from /v1/models, the page is stale.

What does the catalog list for price and context?

GPT-5.1-Codex is listed at $1.25 / 1M tokens input and $10 / 1M tokens output. Context window: 400000 tokens.

What should I treat as unverified?

Do not call it if first-party CacheSafety Bench results are a required decision input. This exact model has no published CacheSafety row, so no Safe Hit, Bad Hit, or trap rate is stated for it.

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