Grok 4 Fast Reasoning

Grok 4 Fast Reasoning by xAI via AnyFast OpenAI-compatible API. Grok 4 with reasoning.

Grok 4 Fast Reasoning is available through AnyFast via an OpenAI-compatible interface. Grok 4 with reasoning.

Key capabilities

• OpenAI-compatible — Works as a drop-in replacement with the OpenAI SDK
• Streaming — Supports real-time token streaming via SSE
• Strong reasoning — Designed for complex, multi-step tasks

Quick example

cURL

curl https://www.anyfast.ai/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "grok-4-fast-reasoning",
    "messages": [
      { "role": "user", "content": "Explain quantum entanglement in simple terms." }
    ]
  }'

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://www.anyfast.ai/v1"
)

response = client.chat.completions.create(
    model="grok-4-fast-reasoning",
    messages=[
        {"role": "user", "content": "Explain quantum entanglement in simple terms."}
    ]
)

print(response.choices[0].message.content)

Parameters

Parameter	Type	Required	Description
model	string	Yes	Must be grok-4-fast-reasoning
messages	array	Yes	List of { role, content } objects
max_tokens	integer	No	Maximum tokens to generate
temperature	float	No	0–2. Controls randomness. Default: 1
stream	boolean	No	Enable SSE streaming. Default: false
top_p	float	No	Nucleus sampling threshold

API Reference

View the interactive API playground for Grok 4 Fast Reasoning.