OpenAI: GPT 5.1

gpt-5.1

GPT 5.1 costs $1.63 per million input tokens and $13.00 per million output tokens, supports 400K context, and is available through the OpenAI-compatible API.

Optimized GPT-5.1 routing for lower latency and higher availability.

Modalities

Text + Image → Text

Input / output price

$1.63 / $13.00 per 1M

Context

400K · max output 128K

Capabilities

ReasoningVisionTool callingLong context

Pricing

Billed per token actually used and deducted from your credits.

ItemUSD per 1M tokens
Input$1.63
Output$13.00
Cached input$0.163

Calculator

Drag the sliders to estimate what this model will cost.

Per request
$0.0153
Per day
$7.64
Per month (30 days)
$229.13

GPT 5.1: input $1.625/M · output $13/M · cached input $0.1625/M

Request with these settings
curl https://api.geniusrelaygpt.com/v1/chat/completions \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "gpt-5.1", "max_tokens": 800,
       "messages": [{"role": "user", "content": "…"}]}'

Code samples

OpenAI-compatible. Set the base URL to https://api.geniusrelaygpt.com/v1 and the model to gpt-5.1.

curl https://api.geniusrelaygpt.com/v1/chat/completions \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.1",
    "stream": true,
    "messages": [{"role": "user", "content": "Hello"}]
  }'

Use it in a client: Cursor · Cline · SillyTavern · Codex

Parameters

Common OpenAI parameters can be passed as-is.

temperaturetop_pmax_tokensstreamstoppresence_penaltyfrequency_penaltyseed

FAQ

How is GPT 5.1 billed?
Input is $1.63 and output is $13.00 per million tokens; cached input is $0.163. The charge for every request is listed in Usage Logs in the console.
How long is the context window?
400K tokens. In a long conversation every turn is billed for the full input, so keep the history under control.
Does it support streaming?
Yes. Add "stream": true to the request to receive server-sent events in the OpenAI format.
GPT 5.1 API pricing · GeniusRelay