OpenRouter AI Models Guide

OpenRouter provides a unified API for 200+ AI models. This guide covers model selection, pricing, routing, and integration with SperaxOS.

What Is OpenRouter?

A single API endpoint that routes requests to 200+ models:

Your App → OpenRouter API → Model Provider
                              ├── OpenAI (GPT-4, o1, o3)
                              ├── Anthropic (Claude 4, Sonnet, Haiku)
                              ├── Google (Gemini 2.5, Pro, Flash)
                              ├── Meta (Llama 4, Maverick)
                              ├── Mistral (Large, Medium)
                              ├── DeepSeek (V3, R1)
                              └── 50+ more providers

Quick Start

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-sonnet-4-20250514",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

Model Selection Guide

By Task

Task	Recommended Model	Why
Complex reasoning	claude-sonnet-4, o3	Best logical reasoning
Coding	claude-sonnet-4, deepseek-v3	Best code generation
Creative writing	claude-sonnet-4, gpt-4o	Most creative output
Fast responses	gemini-flash, claude-haiku	Lowest latency
Long context	gemini-pro-2.5 (1M), claude-sonnet-4 (200K)	Largest context windows
DeFi analysis	claude-sonnet-4, gpt-4o	Best structured data handling
Vision/images	gpt-4o, gemini-pro	Best image understanding
JSON output	claude-sonnet-4, gpt-4o	Most reliable structured output
Budget	deepseek-v3, llama-4	Cheapest per token

By Price (per 1M tokens)

Tier	Input	Output	Models
Free	$0	$0	Selected models with limits
Budget	$0.10-0.50	$0.30-1.50	DeepSeek, Llama, Gemma
Standard	$1-5	$3-15	GPT-4o, Claude Sonnet, Gemini Pro
Premium	$10-15	$30-60	o3, Claude Opus

By Context Window

Model	Context	Best For
Gemini 2.5 Pro	1,048,576	Entire codebases
Claude Sonnet 4	200,000	Long documents
GPT-4o	128,000	Standard tasks
DeepSeek V3	64,000	Budget long-context

Routing Strategies

Automatic Routing

Let OpenRouter pick the best model:

{
  "model": "openrouter/auto",
  "messages": [...]
}

Fallback Chain

Define fallback models if primary is unavailable:

{
  "model": "anthropic/claude-sonnet-4-20250514",
  "route": "fallback",
  "models": [
    "anthropic/claude-sonnet-4-20250514",
    "openai/gpt-4o",
    "google/gemini-2.5-pro"
  ]
}

Cheapest Route

Use the cheapest available model for a task:

{
  "model": "openrouter/cheapest",
  "max_price": { "prompt": 0.001, "completion": 0.003 }
}

SperaxOS Integration

SperaxOS uses OpenRouter as a model provider:

Configuration

# .env
OPENROUTER_API_KEY=sk-or-...
OPENROUTER_MODEL_LIST=anthropic/claude-sonnet-4-20250514,openai/gpt-4o,google/gemini-2.5-pro

Model Data File

SperaxOS maintains a curated model list at data/openrouter-models.ts:

• Pre-selected models optimized for DeFi/crypto tasks
• Pricing and capability metadata
• Context window sizes
• Feature flags (vision, function calling, JSON mode)

Per-Agent Model Selection

Different SperaxOS agents can use different models:

• DeFi Advisor: Claude Sonnet 4 (best reasoning)
• Quick Chat: Gemini Flash (fastest response)
• Code Assistant: DeepSeek V3 (budget coding)
• Research Agent: Gemini 2.5 Pro (largest context)

API Compatibility

OpenRouter is compatible with:

• OpenAI SDK (just change base URL)
• LangChain
• LlamaIndex
• Vercel AI SDK
• Any OpenAI-compatible client

import OpenAI from 'openai';

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

Links

• Website: https://openrouter.ai
• Docs: https://openrouter.ai/docs
• Models: https://openrouter.ai/models
• GitHub: https://github.com/nirholas/openrouter-models
• SperaxOS: https://app.sperax.io