OpenAI: GPT-5.1 Chat

openai/gpt-5.1-chat

Chat

GPT-5.1 Chat (AKA Instant is the fast, lightweight member of the 5.1 family, optimized for low-latency chat while retaining strong general intelligence. It uses adaptive reasoning to selectively “think” on harder queries, improving accuracy on math, coding, and multi-step tasks without slowing down typical conversations. The model is warmer and more conversational by default, with better instruction following and more stable short-form reasoning. GPT-5.1 Chat is designed for high-throughput, interactive workloads where responsiveness and consistency matter more than deep deliberation.

by OpenAI

Input type: Output type: Publish time: 2025-11-13

Recent activity on GPT-5.1 Chat

Tokens processed per day

Throughput

(tokens/s)

First Token Latency

(ms)

Uptime stats for GPT-5.1 Chat

Uptime stats for GPT-5.1 Chat across all providers

Uptime

Azure | OpenAI

( Percent )

| Providers for GPT-5.1 Chat |

ZenMux Provider to the best providers that are able to handle your prompt size and parameters, with fallbacks to maximize uptime.

OpenAI

Latency

Throughput

Uptime

Recent uptime

Apr 30, 2026 6:00 PM-

Price

Input: $ 1.25/ M tokens

Output: $ 10/ M tokens

Cache read: $ 0.125/ M tokens

Cache write 5m

Cache write 1h

Cache write

Web search: $ 0.01/ counts

Model limitation

Context: 128.00K

Max output: 16.38K

Sample code and API for GPT-5.1 Chat

ZenMux normalizes requests and responses across providers for you.

Create API Key

from openai import OpenAI

client = OpenAI(
  base_url="https://zenmux.ai/api/v1",
  api_key="<ZENMUX_API_KEY>",
)

# Chat Completion
completion = client.chat.completions.create(
  model="openai/gpt-5.1-chat",
  messages=[
    {
      "role": "user",
      "content": "What is the meaning of life?"
    }
  ]
)
print(completion.choices[0].message.content)

# Responses API
responses = client.responses.create(
  model="openai/gpt-5.1-chat",
  input="What is the meaning of life?"
)
print(responses)