xAIPaidOperational
Grok 4 Fast Reasoning
API model name: grok-4-fast-reasoning
Grok 4 Fast Reasoning is xAI's chat model, served on the Api.Airforce unified API. Capabilities include Reasoning. It is priced at $0.02 per million input tokens and $0.04 per million output tokens. Access it through the OpenAI-compatible API with one key, alongside 100+ other models on Api.Airforce.
Pricing
Specifications
- Provider
- xAI
- Type
- chat model
Capabilities
Reasoning
What is Grok 4 Fast Reasoning used for?
- Chatbots & assistants — conversational AI, drafting, summarizing and Q&A.
- Complex reasoning — math, coding and step-by-step problem solving.
Grok 4 Fast Reasoning vs. similar models
| Model | Intelligence | Context | Input / 1M | Output / 1M |
|---|---|---|---|---|
| Grok 4 Fast Reasoning | — | — | $0.02 | $0.04 |
| Grok 2 Vision | — | — | $3.12 | $15.57 |
| Grok 3 | 18.4 | — | $2.91 | $14.55 |
| Grok 3 Deepsearch | — | — | $0.57 | $2.89 |
Prices are Api.Airforce pay-as-you-go rates per 1M tokens. Context is the maximum input length.
Related models
Grok 2 VisionxAI · $3.12 / 1MGrok 3xAI · $2.91 / 1MGrok 3 DeepsearchxAI · $0.57 / 1MGrok 3 FastxAI · $4.74 / 1MGrok 3 MinixAI · $0.51 / 1MGrok 3 Mini FastxAI · $0.93 / 1MGrok 3 ReasonerxAI · $0.57 / 1MGrok 4xAI · $1.64 / 1MGrok 4xAI · $2.07 / 1MGrok 4.20 ReasoningxAI · $0.27 / 1MGrok 4 FastxAI · $0.20 / 1MGrok 4.1 FastxAI · $0.15 / 1M
Grok 4 Fast Reasoning — frequently asked questions
- How much does Grok 4 Fast Reasoning cost?
- Grok 4 Fast Reasoning is billed pay-as-you-go at $0.02 per 1M input tokens and $0.04 per 1M output tokens. There is no subscription — you only pay for what you use.
- What can Grok 4 Fast Reasoning do?
- Grok 4 Fast Reasoning supports Reasoning.
- Is Grok 4 Fast Reasoning free to use?
- Grok 4 Fast Reasoning is a paid, pay-as-you-go model — no subscription, you are only charged for usage.
- How do I use Grok 4 Fast Reasoning via the API?
- Grok 4 Fast Reasoning is OpenAI-compatible. Point any OpenAI SDK at https://api.airforce/v1 and pass the model ID grok-4-fast-reasoning with your Api.Airforce API key.
- Who makes Grok 4 Fast Reasoning?
- Grok 4 Fast Reasoning is xAI's chat model, served through the unified Api.Airforce gateway alongside 100+ other models.
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Use Grok 4 Fast Reasoning via the API
OpenAI-compatible — point any OpenAI SDK at https://api.airforce/v1 and pass grok-4-fast-reasoning as the model.
cURL
curl https://api.airforce/v1/chat/completions \
-H "Authorization: Bearer $AIRFORCE_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "grok-4-fast-reasoning",
"messages": [{ "role": "user", "content": "Hello!" }]
}'Python
from openai import OpenAI
client = OpenAI(base_url="https://api.airforce/v1", api_key="$AIRFORCE_API_KEY")
r = client.chat.completions.create(
model="grok-4-fast-reasoning",
messages=[{"role": "user", "content": "Hello!"}],
)
print(r.choices[0].message.content)JavaScript
import OpenAI from "openai";
const client = new OpenAI({ baseURL: "https://api.airforce/v1", apiKey: process.env.AIRFORCE_API_KEY });
const r = await client.chat.completions.create({
model: "grok-4-fast-reasoning",
messages: [{ role: "user", content: "Hello!" }],
});
console.log(r.choices[0].message.content);