OpenRouter LLM Example

This example demonstrates how to use OpenRouter with langchaingo. OpenRouter provides a unified API to access various LLM models through a single endpoint.

About OpenRouter

OpenRouter is an AI routing service that provides:

• Access to multiple LLM providers (OpenAI, Anthropic, Google, Meta, etc.) through a single API
• Automatic failover and load balancing
• Usage tracking and analytics
• Support for both free and premium models

Setup

1. Get an OpenRouter API key from https://openrouter.ai/
2. Set the environment variable:
   bashCopy

   export OPENROUTER_API_KEY="your-api-key-here"
   

Usage

OpenRouter uses an OpenAI-compatible API, so you can use the OpenAI client with a custom base URL:

llm, err := openai.New(
    openai.WithModel("meta-llama/llama-3.2-3b-instruct:free"),
    openai.WithBaseURL("https://openrouter.ai/api/v1"),
    openai.WithToken(apiKey),
)

Available Models

OpenRouter provides access to many models including:

• Free tier: meta-llama/llama-3.2-3b-instruct:free, google/gemma-2-9b-it:free
• Premium: GPT-4, Claude, Gemini Pro, and many more
• Check https://openrouter.ai/models for the full list

Running the Example

go run openrouter_llm_example.go

Features

• ✅ Streaming responses supported
• ✅ Compatible with OpenAI client
• ✅ Access to multiple model providers
• ✅ Automatic handling of provider-specific quirks