OpenRouter Provider

OpenRouter provides access to 400+ AI models from dozens of providers through a single API. This is ideal for:

Multi-model workflows - Switch between Claude, GPT, Llama, and more
Cost optimization - Route to the cheapest available provider
Fallback resilience - Automatic failover when models are unavailable
Unified billing - Single API key for all providers

Setup

Set your OpenRouter API key:

export OPENROUTER_API_KEY=sk-or-...

Optional analytics configuration:

export OPENROUTER_SITE_URL="https://myapp.com"    # Your app URL
export OPENROUTER_APP_NAME="MyApp"                 # Your app name

Model Format

OpenRouter models use the format provider/model-name:

openrouter:anthropic/claude-sonnet-4-5
openrouter:openai/gpt-4o
openrouter:deepseek/deepseek-chat
openrouter:meta-llama/llama-3.3-70b-instruct

Popular Models

Model	OpenRouter ID	Best For
Claude Sonnet 4.5	`anthropic/claude-sonnet-4-5`	Balanced performance
GPT-4o	`openai/gpt-4o`	General tasks, vision
DeepSeek Chat (V3)	`deepseek/deepseek-chat`	Cost-effective coding
DeepSeek R1	`deepseek/deepseek-r1`	Complex reasoning
Llama 3.3 70B	`meta-llama/llama-3.3-70b-instruct`	Open-source option
Gemini 2.5 Flash	`google/gemini-2.5-flash`	Fast, long context

Quick Aliases

llmist provides shortcuts for common OpenRouter models:

Alias	Full Model
`or:sonnet`	`openrouter:anthropic/claude-sonnet-4-5`
`or:opus`	`openrouter:anthropic/claude-opus-4-5`
`or:haiku`	`openrouter:anthropic/claude-haiku-4-5`
`or:gpt4o`	`openrouter:openai/gpt-4o`
`or:gpt5`	`openrouter:openai/gpt-5.2`
`or:flash`	`openrouter:google/gemini-2.5-flash`
`or:llama`	`openrouter:meta-llama/llama-3.3-70b-instruct`
`or:deepseek`	`openrouter:deepseek/deepseek-r1`

Usage Examples

import { LLMist } from 'llmist';

const answer = await LLMist.createAgent()
  .withModel('openrouter:deepseek/deepseek-chat')
  .askAndCollect('Explain async/await in JavaScript');

import { LLMist } from 'llmist';

// Use the or: prefix for quick access
const answer = await LLMist.createAgent()
  .withModel('or:sonnet')
  .askAndCollect('Write a haiku about coding');

# Full model ID
npx @llmist/cli complete "Hello" --model openrouter:deepseek/deepseek-chat

# Using alias
npx @llmist/cli agent "Review my code" --model or:sonnet

Routing Options

OpenRouter supports intelligent routing to optimize for cost, speed, or quality:

import { LLMist } from 'llmist';

const answer = await LLMist.createAgent()
  .withModel('openrouter:deepseek/deepseek-chat')
  .withExtra({
    routing: {
      route: 'cheapest',  // 'cheapest' | 'fastest' | 'quality'
    },
  })
  .askAndCollect('Hello!');

Route Options

Option	Description
`quality`	Best quality provider (default)
`cheapest`	Lowest cost provider
`fastest`	Lowest latency provider

Model Fallbacks

Configure automatic fallback to alternative models:

import { LLMist } from 'llmist';

const answer = await LLMist.createAgent()
  .withModel('openrouter:anthropic/claude-sonnet-4-5')
  .withExtra({
    routing: {
      // Try these models in order if primary is unavailable
      models: [
        'anthropic/claude-sonnet-4-5',
        'openai/gpt-4o',
        'deepseek/deepseek-chat',
      ],
    },
  })
  .askAndCollect('Complex analysis task...');

Provider Routing

Route to a specific provider when a model is available from multiple sources:

const answer = await LLMist.createAgent()
  .withModel('openrouter:meta-llama/llama-3.3-70b-instruct')
  .withExtra({
    routing: {
      provider: 'Together',  // Route to Together AI
      // Or specify provider preference order:
      // order: ['Together', 'Fireworks', 'Anyscale'],
    },
  })
  .askAndCollect('Hello!');

Manual Configuration

For advanced setups, configure the provider manually:

import { LLMist, OpenRouterProvider } from 'llmist';
import OpenAI from 'openai';

const openRouterClient = new OpenAI({
  apiKey: process.env.OPENROUTER_API_KEY,
  baseURL: 'https://openrouter.ai/api/v1',
});

const client = new LLMist({
  autoDiscoverProviders: false,
  adapters: [
    new OpenRouterProvider(openRouterClient, {
      siteUrl: 'https://myapp.com',
      appName: 'MyApp',
    }),
  ],
});

Access models not directly supported (Llama, Mistral, Qwen, etc.)
Need automatic failover between providers
Want unified billing across multiple models
Optimizing for cost with dynamic routing
Testing different models quickly

Cost Tracking

OpenRouter passes through usage information:

for await (const event of agent.run()) {
  if (event.type === 'llm_call_complete') {
    console.log('Input tokens:', event.usage?.promptTokens);
    console.log('Output tokens:', event.usage?.completionTokens);
    console.log('Estimated cost:', event.cost);
  }
}

Error Handling

The OpenRouter provider includes enhanced error messages:

Error	Meaning
401	Invalid API key - check `OPENROUTER_API_KEY`
402	Insufficient credits - add funds at openrouter.ai/credits
429	Rate limit exceeded - reduce request frequency
503	Model unavailable - try a different model or use fallbacks

Reasoning Models via OpenRouter

OpenRouter provides access to reasoning-capable models like DeepSeek R1, which excels at math, logic, and coding with chain-of-thought reasoning:

const answer = await LLMist.createAgent()
  .withModel('openrouter:deepseek/deepseek-r1')
  .askAndCollect('Prove there are infinitely many primes.');