Grok 4.1 Fast Reasoning

spacexai/grok-4.1-fast-reasoning

A chat model with a 1M-token context window, at $0.21 per million input tokens and $0.525 per million output tokens.

Details

Maker: spacexai
Kind: Chat
Context window: 1,000,000 tokens
Max output: 1,000,000 tokens
Input: $0.21 per million tokens
Cached input: $0.0525 per million tokens, 75% off
Cache write: Same as input
Output: $0.525 per million tokens
Capabilities: Reasoning, tool use, vision, file input
Takes: Text, image, pdf
Returns: Text
Zero data retention: Yes, on every provider
No training on requests: Yes, on every provider
Released: 2025-11-19

Call it

curl

curl https://phantom.codes/v1/chat/completions \
  -H "Authorization: Bearer $PHANTOM_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "spacexai/grok-4.1-fast-reasoning",
    "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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