How much does Grok 4 Fast cost?

Grok 4 Fast is billed pay-as-you-go at $0.15 per 1M input tokens and $0.37 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.

xAIPaidOperational

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 $0.15 per million input tokens and $0.37 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.

Get an API key View pricing

Pricing

Input / 1M tokens

$0.15

Output / 1M tokens

$0.37

Cache read / 1M tokens

$0.04

Official input rate

$0.20

Official output rate

$0.50

Api.Airforce price vs. the provider's official rate.

Pricing by input length

Input length	Input / 1M tokens	Output / 1M tokens
≤127999	$0.15	$0.37
long_context	$0.15	$0.37

Specifications

Provider: xAI
Type: chat model

Capabilities

Reasoning

Benchmarks

Independent evaluations and measured speed from Artificial Analysis.

Intelligence Index

27.4/100

Math Index

89.7/100

MMLU-Pro85%

GPQA Diamond85%

Humanity's Last Exam17%

LiveCodeBench83%

AIME 202590%

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	27.4	—	$0.15	$0.37
Grok 3	18.4	—	—	—
Grok 3 Deepsearch	—	—	$0.42	$2.13
Grok 3 Fast	—	—	$7.77	$38.88

Prices are Api.Airforce pay-as-you-go rates per 1M tokens. Context is the maximum input length.

Grok 4 Fast — frequently asked questions

How much does Grok 4 Fast cost?: Grok 4 Fast is billed pay-as-you-go at $0.15 per 1M input tokens and $0.37 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.

All models·Quickstart·Chat API reference

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

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!" }]
  }'

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",
    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",
  messages: [{ role: "user", content: "Hello!" }],
});
console.log(r.choices[0].message.content);