Using OpenRouter to access multiple AI models

Managing API keys for every AI provider is tedious. OpenAI needs one key, Anthropic needs another, Google has its own setup. If you want to compare models or switch between them based on the task, you end up juggling multiple accounts and billing dashboards.

OpenRouter solves this by giving you a single API endpoint and one API key that routes to any supported model.

How it works

OpenRouter sits between your application and the model providers. You send requests to the OpenRouter API in the standard OpenAI format, specify which model you want, and OpenRouter handles the rest. Authentication, billing, rate limiting, all through one account.

The API is compatible with the OpenAI SDK, so if you have code that already talks to OpenAI, switching to OpenRouter is usually a one-line change:

import OpenAI from "openai";
 
const client = new OpenAI({
  baseURL: "https://openrouter.ai/api/v1",
  apiKey: process.env.OPENROUTER_API_KEY,
});
 
const response = await client.chat.completions.create({
  model: "anthropic/claude-sonnet-4",
  messages: [{ role: "user", content: "Hello!" }],
});

That is it. Same SDK, different base URL and model name.

Why I use it

Model comparison. When I am evaluating which model works best for a task, I can try Claude, GPT-4, Gemini, and Llama all from the same code. No SDK changes, no separate auth flows.

Cost optimization. Different models have different price points. For simple tasks, a cheaper model works fine. For complex reasoning, I reach for Claude or GPT-4. OpenRouter makes it easy to route based on the task without infrastructure changes.

Fallback routing. If one provider has an outage, OpenRouter can automatically fall back to another model. This matters for production applications where uptime is critical.

Available models

The model selection is extensive. As of writing, OpenRouter supports models from OpenAI, Anthropic, Google, Meta, Mistral, and many others. Each model is identified by a provider/model-name format like anthropic/claude-sonnet-4 or openai/gpt-4o.

You can browse the full list at openrouter.ai/models with pricing, context window sizes, and capabilities for each.

Pricing

OpenRouter charges per token, same as the providers themselves. The markup is minimal. For most models, the price is identical or very close to what you would pay going direct. The convenience of a single account and unified billing is worth it.

For local development

OpenRouter also works well with tools that support the OpenAI API format. Point your AI coding assistant, chat UI, or automation tool at the OpenRouter endpoint, and you get access to the full model catalog without any custom integration work.

I use it with Open WebUI as an alternative to running everything locally. When I need a model that is too large for my hardware, I route through OpenRouter instead of running it on Ollama.

Sources

• OpenRouter
• OpenRouter Documentation