Grok 4 Fast
API model name: grok-4-fast
Grok 4 Fast is xAI's chat model, served on the Api.Airforce unified API. Capabilities include Reasoning. It is priced at $0.21 per million input tokens and $0.53 per million output tokens. That is below the provider's $0.20 official input rate. Access it through the OpenAI-compatible API with one key, alongside 100+ other models on Api.Airforce.
Pricing
Api.Airforce price vs. the provider's official rate.
Pricing by input length
| Input length | Input / 1M tokens | Output / 1M tokens |
|---|---|---|
| Up to 127999 input tokens | $0.21 | $0.53 |
| From 128000 input tokens | $0.52 | $1.30 |
Specifications
- Provider
- xAI
- Type
- chat model
Capabilities
Benchmarks
Independent evaluations and measured speed from Artificial Analysis.
Grok 4 Fast (Reasoning) · 11.1–17.9
Source: Benchmark data by Artificial Analysis (artificialanalysis.ai)
What is Grok 4 Fast used for?
- Chatbots & assistants — conversational AI, drafting, summarizing and Q&A.
- Complex reasoning — math, coding and step-by-step problem solving.
Grok 4 Fast vs. similar models
| Model | Intelligence | Context | Input / 1M | Output / 1M |
|---|---|---|---|---|
| Grok 4 Fast | 17.9 | — | $0.21 | $0.53 |
| Grok 2 Vision | — | — | $2.10 | $10.50 |
| Grok 3 | 12.1 | — | $3.50 | $17.50 |
| Grok 3 Deepersearch | — | — | $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 4 Fast — frequently asked questions
- How much does Grok 4 Fast cost?
- Grok 4 Fast is billed pay-as-you-go at $0.21 per 1M input tokens and $0.53 per 1M output tokens. There is no subscription — you only pay for what you use.
- What can Grok 4 Fast do?
- Grok 4 Fast supports Reasoning.
- Is Grok 4 Fast free to use?
- Grok 4 Fast is a paid, pay-as-you-go model — no subscription, you are only charged for usage.
- How do I use Grok 4 Fast via the API?
- Grok 4 Fast is OpenAI-compatible. Point any OpenAI SDK at https://api.airforce/v1 and pass the model ID grok-4-fast with your Api.Airforce API key.
- Who makes Grok 4 Fast?
- Grok 4 Fast is xAI's chat model, served through the unified Api.Airforce gateway alongside 100+ other models.
Use Grok 4 Fast via the API
OpenAI-compatible — point any OpenAI SDK at https://api.airforce/v1 and pass grok-4-fast as the model.
curl https://api.airforce/v1/chat/completions \
-H "Authorization: Bearer $AIRFORCE_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "grok-4-fast",
"messages": [{ "role": "user", "content": "Hello!" }]
}'from openai import OpenAI
client = OpenAI(base_url="https://api.airforce/v1", api_key="$AIRFORCE_API_KEY")
r = client.chat.completions.create(
model="grok-4-fast",
messages=[{"role": "user", "content": "Hello!"}],
)
print(r.choices[0].message.content)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",
messages: [{ role: "user", content: "Hello!" }],
});
console.log(r.choices[0].message.content);