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GPT-5 mini (Fast)

openai/gpt-5-mini-fast

A chat model with a 400K-token context window, at $0.4725 per million input tokens and $3.78 per million output tokens.

Details

Maker
openai
Kind
Chat
Context window
400,000 tokens
Max output
128,000 tokens
Input
$0.4725 per million tokens
Cached input
$0.04725 per million tokens, 90% off
Cache write
Same as input
Output
$3.78 per million tokens
Capabilities
Reasoning, tool use, vision, file input, web search, fast
Takes
Text, image, pdf
Returns
Text
Zero data retention
Yes, on every provider
No training on requests
Yes, on every provider
Released
2025-08-07
Newer model
openai/gpt-6-lunaReleased later by the same maker, costs no more, and lists the same capabilities. Compare the two

Description

GPT-5 mini is a cost optimized model that excels at reasoning/chat tasks. It offers an optimal balance between speed, cost, and capability.

Call it

curl
curl https://phantom.codes/v1/chat/completions \
  -H "Authorization: Bearer $PHANTOM_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-5-mini-fast",
    "messages": [
      {"role": "user", "content": "Hello"}
    ]
  }'

Set PHANTOM_KEY to your key. Any OpenAI client works with the base URL https://phantom.codes/v1.

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