Using Grok 4.1 Fast on Vercel AI Gateway

Implementation guide · Grok 4 · xAI

Serverless

Vercel AI Gateway exposes Grok 4.1 Fast through model ID spacexai/grok-4.1-fast-reasoning. Use the setup steps, sourced pricing, capabilities, and official provider links below to validate this route before deployment.

Last refreshed 2026-10-18. Next refresh: weekly.

Quick Start

1
Create an account at Vercel AI Gateway and generate an API key.
2
Use the Vercel AI Gateway SDK or REST API to call spacexai/grok-4.1-fast-reasoning — see the documentation for request format.
3
You'll be billed $0.20/1M input, $0.50/1M output tokens. See full pricing.

API Portal Documentation Pricing

Code Examples

Install

pip install openai

API key

AI_GATEWAY_API_KEY

Model ID

spacexai/grok-4.1-fast-reasoning

creator/model-name e.g. kwaipilot/kat-coder-pro-v2

import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["AI_GATEWAY_API_KEY"],
    base_url="https://ai-gateway.vercel.sh/v1"
)
response = client.chat.completions.create(
    model="spacexai/grok-4.1-fast-reasoning",
    messages=[{"role": "user", "content": "Hello"}]
)
print(response.choices[0].message.content)

Pricing on Vercel AI Gateway

Type	Price (per 1M)
Input tokens	$0.20
Output tokens	$0.50

Capabilities

VisionMultimodalReasoningJSON / Tool useStructured Outputs

About Grok 4.1 Fast

Ultra-low latency Grok 4.1 Fast API family. xAI retired grok-4-1-fast-reasoning and grok-4-1-fast-non-reasoning on 2026-05-15; requests now redirect to Grok 4.3 at Grok 4.3 pricing.

Full model details →

Model Specs

Released2025-11-19

Context2M

Vercel