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NEW GPT-5.5 / Claude 4.6 is now live — try it today →

One Key, Every Leading AI Model

OpenAI · Claude · Gemini · DeepSeek — 79+ models, fully compatible

CNY Settlement · Below Official Pricing · Pay-as-you-go
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Integrated 10+ Top-tier AI Providers

Core Advantages

One Key. Rock Solid.

Unified API · Transparent Pricing · Intelligent Routing · Enterprise Security

Unified API, One Key

Fully compatible with OpenAI SDK. Zero code changes to access 79+ models. Integrate once, use everywhere.

1 Key → 79+ Models

Transparent Pricing, CNY Settlement

Pay-as-you-go, failed requests not billed. Alipay / WeChat supported, invoices available.

0 Failed Requests Billed

High Availability, Smart Routing

Multi-node distributed deployment, automatic failover. 99.9%+ uptime, your business never sleeps.

99.9% Uptime · Multi-Node Failover

Data Security & Compliance

No request content storage. Zero Data Retention support. Enterprise-grade compliance standards.

ZDR Zero Data Retention · Encrypted
Why Choose Us

Lower Price. More Models. Rock Solid.

Below Official Pricing

Bulk procurement and optimized routing cut costs, passing savings directly to developers.

Full Model Coverage

79+ models in one place. No more juggling multiple provider agreements.

CNY Settlement

Alipay, WeChat Pay, and bank transfer accepted. No foreign credit card required.

Enterprise-grade Security

ZDR zero data retention, TLS encryption, audit logs. Full compliance ready.

Price Comparison · Claude Opus

Official Price ¥56 / 1M
Our Price
¥46 / 1M Save ~18%
Official + Failed Requests Billed ¥60+ / 1M

* Failed requests are not billed · Based on 30-day average

Quick Start

3 Steps to Start Calling

Register → Copy Code → Send Request. Less than 1 minute.

1. Register & Get Key

One-click registration in console. Generate your API key and get free credits instantly.

2. Install SDK

Python, Node.js, Java, Go — one command to install. OpenAI SDK works out of the box.

3. First API Call

Replace base_url, copy the sample code, and get a response instantly.

from openai import OpenAI

client = OpenAI(
    api_key="sk-your-api-key",
    base_url="https://api.onefast.ai/v1"
)

response = client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {"role": "system", "content": "You are a helpful AI assistant."},
        {"role": "user",   "content": "Hello, introduce yourself in one sentence."}
    ]
)

print(response.choices[0].message.content)
import OpenAI from "openai";

const client = new OpenAI({
  apiKey: "sk-your-api-key",
  baseURL: "https://api.onefast.ai/v1"
});

const response = await client.chat.completions.create({
  model: "gpt-4o",
  messages: [
    { role: "system", content: "You are a helpful AI assistant." },
    { role: "user",   content: "Hello, introduce yourself in one sentence." }
  ]
});

console.log(response.choices[0].message.content);
curl https://api.onefast.ai/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sk-your-api-key" \
  -d '{
    "model": "gpt-4o",
    "messages": [
      {"role": "system", "content": "You are a helpful AI assistant."},
      {"role": "user",   "content": "Hello, introduce yourself in one sentence."}
    ]
  }'
Testimonials

Trusted by Developers Worldwide

From startups to large enterprises, thousands of developers are building with Westtree

Our product calls multiple LLMs under the hood. Maintaining our own gateway was expensive and painful. After switching to this platform, we completed all integrations in 2 days — fully OpenAI-compatible, near-zero migration cost. Running for almost a year with 99.9%+ uptime.

WL
Wenbo Li
CTO · OMRON

We provide AI coding assistants and essay grading tools for students. The previous service was expensive and unstable. After switching, stability improved significantly and bulk pricing is very competitive.

SW
Siyuan Wang
Product Director · SCIYON

I need to test different models for research. Official APIs are either inaccessible or too expensive. This platform has full model coverage, student-friendly pricing, and OpenAI SDK works with just one line change. So convenient.

SH
Haoran Sun
Graduate Researcher
FAQ

Still Have Questions?

Register for an account, generate an API key in the console, copy it into your code, and replace base_url with our address. All OpenAI SDK-compatible code works out of the box.
Yes. We reduce overall costs through bulk procurement and intelligent routing, passing savings to developers. Most models are 10%–20% below official pricing, with failed requests free of charge.
No. By default, we do not store any request/response content. Enterprise accounts can enable Zero Data Retention (ZDR) mode for even stricter guarantees. All traffic is encrypted via TLS.
Any language with OpenAI API-compatible SDKs: Python, Node.js, Java, Go, PHP, Ruby, and more. Native HTTP APIs and cURL examples are also available.
Free-tier users can use community resources and docs. Professional plans include email support. Enterprise plans come with 24/7 dedicated support and SLO guarantees.

Start Building Today

Free credits on sign-up. No credit card required. 1 minute to get started.