Quick Start

ARouter gives you one API key and one endpoint for leading LLM providers. If you already use an OpenAI-compatible client, the migration is usually just base_url, api_key, and optionally your app attribution headers.

1. Get Your API Key

2. Install the ARouter SDK

The first-party @arouter/sdk works in any Node.js or TypeScript project and supports npm, yarn, and pnpm.

npm
yarn
pnpm

npm install @arouter/sdk

yarn add @arouter/sdk

pnpm add @arouter/sdk

import { ARouter } from "@arouter/sdk";

const client = new ARouter({
  apiKey: "lr_live_xxxx",
  baseURL: "https://api.arouter.ai",
});

const response = await client.chatCompletion({
  model: "openai/gpt-5.4",
  messages: [{ role: "user", content: "Hello!" }],
});
console.log(response.choices[0].message.content);

See the Node.js / TypeScript SDK guide for streaming, key management, and x402 payment examples.

3. Use Your Existing SDK

Already using OpenAI, Anthropic, or Go? The only changes are base_url and api_key.

from openai import OpenAI

client = OpenAI(
    base_url="https://api.arouter.ai/v1",
    api_key="lr_live_xxxx",
    default_headers={
        "HTTP-Referer": "https://myapp.com",  # Optional
        "X-Title": "My AI App",               # Optional
    },
)

response = client.chat.completions.create(
    model="openai/gpt-5.4",
    messages=[{"role": "user", "content": "Hello!"}],
)
print(response.choices[0].message.content)

import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.arouter.ai/v1",
  apiKey: "lr_live_xxxx",
  defaultHeaders: {
    "HTTP-Referer": "https://myapp.com", // Optional
    "X-Title": "My AI App",              // Optional
  },
});

const response = await client.chat.completions.create({
  model: "openai/gpt-5.4",
  messages: [{ role: "user", content: "Hello!" }],
});
console.log(response.choices[0].message.content);

import anthropic

client = anthropic.Anthropic(
    base_url="https://api.arouter.ai",
    api_key="lr_live_xxxx",
)

message = client.messages.create(
    model="claude-sonnet-4.6",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Hello!"}],
)
print(message.content[0].text)

package main

import (
    "context"
    "fmt"
    "log"

    "github.com/arouter-ai/arouter-go"
)

func main() {
    client := arouter.NewClient("lr_live_xxxx",
        arouter.WithBaseURL("https://api.arouter.ai/v1"),
        arouter.WithHeader("HTTP-Referer", "https://myapp.com"),
        arouter.WithHeader("X-Title", "My AI App"),
    )

    resp, err := client.CreateChatCompletion(context.Background(), arouter.ChatCompletionRequest{
        Model: "openai/gpt-5.4",
        Messages: []arouter.Message{
            {Role: "user", Content: "Hello!"},
        },
    })
    if err != nil {
        log.Fatal(err)
    }

    fmt.Println(resp.Choices[0].Message.Content)
}

curl https://api.arouter.ai/v1/chat/completions \
  -H "Authorization: Bearer lr_live_xxxx" \
  -H "HTTP-Referer: https://myapp.com" \
  -H "X-Title: My AI App" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-5.4",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

const response = await fetch('https://api.arouter.ai/v1/chat/completions', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer lr_live_xxxx',
    'Content-Type': 'application/json',
    'HTTP-Referer': 'https://myapp.com', // optional: source tracking
    'X-Title': 'My AI App',              // optional: display name
  },
  body: JSON.stringify({
    model: 'openai/gpt-5.4',
    messages: [{ role: 'user', content: 'Hello!' }],
  }),
});

const data = await response.json();
console.log(data.choices[0].message.content);

HTTP-Referer and X-Title are optional. Include them if you want ARouter Dashboard analytics to attribute requests to a specific app or workflow.

4. Use the API Directly

If you prefer not to install an SDK, you can call ARouter with any HTTP client:

import json
import requests

response = requests.post(
    "https://api.arouter.ai/v1/chat/completions",
    headers={
        "Authorization": "Bearer lr_live_xxxx",
        "HTTP-Referer": "https://myapp.com",  # Optional
        "X-Title": "My AI App",               # Optional
        "Content-Type": "application/json",
    },
    data=json.dumps({
        "model": "openai/gpt-5.4",
        "messages": [{"role": "user", "content": "Hello!"}],
    }),
)

print(response.json()["choices"][0]["message"]["content"])

5. Try Different Providers

With ARouter, switching providers is just changing the model string:

# OpenAI
response = client.chat.completions.create(model="openai/gpt-5.4", ...)

# Anthropic (via OpenAI SDK!)
response = client.chat.completions.create(model="anthropic/claude-sonnet-4.6", ...)

# Google Gemini
response = client.chat.completions.create(model="google/gemini-2.5-flash", ...)

# DeepSeek
response = client.chat.completions.create(model="deepseek/deepseek-v3.2", ...)

If you omit the provider prefix (e.g. just "gpt-5.4"), ARouter defaults to OpenAI.

What’s Next?

Authentication

Learn about the three auth methods

Model Routing

Understand the provider/model format and multi-model routing

Billing & Credits

Review pricing, balance, and credit rules

Request Attribution

Attribute traffic to your app in Dashboard analytics

Streaming

Enable real-time streaming responses

Tool Calling

Give models access to your functions

Structured Outputs

Force models to return valid JSON schema

Prompt Caching

Reduce cost and latency for repeated prompts

Key Management

Create scoped keys for your team

FAQ

Common questions answered

Get Started

Core Concepts

Routing

Features

Guides

Privacy

Administration

Best Practices

Frameworks & Integrations

For Providers

Support

1. Get Your API Key

2. Install the ARouter SDK

3. Use Your Existing SDK

4. Use the API Directly

5. Try Different Providers

What’s Next?

Authentication

Model Routing

Billing & Credits

Request Attribution

Streaming

Tool Calling

Structured Outputs

Prompt Caching

Key Management

FAQ

​1. Get Your API Key

​2. Install the ARouter SDK

​3. Use Your Existing SDK

​4. Use the API Directly

​5. Try Different Providers

​What’s Next?

Authentication

Model Routing

Billing & Credits

Request Attribution

Streaming

Tool Calling

Structured Outputs

Prompt Caching

Key Management

FAQ

1. Get Your API Key

2. Install the ARouter SDK

3. Use Your Existing SDK

4. Use the API Directly

5. Try Different Providers

What’s Next?