How to Use the Multi-LLM Router to Compare AI Models

One of the most useful Helix-API services is the Multi-LLM Router — a single endpoint that proxies to every major LLM provider. You write your code once and switch models with a query parameter.

Why route through one API?

• A/B test models without rewriting client code
• Failover automatically if one provider goes down
• Cost-optimize by routing simple requests to cheaper models
• Stay vendor-neutral so you can swap providers without lock-in

The /compare endpoint

The killer feature is /compare: send one prompt, get responses from N models at once.

response = requests.post( "https://multi-llm-router-by-helix-api.p.rapidapi.com/compare", headers={ "X-RapidAPI-Key": "YOUR_KEY", "X-RapidAPI-Host": "multi-llm-router-by-helix-api.p.rapidapi.com", }, json={ "prompt": "Summarize Hamlet in one sentence.", "models": ["llama-3.1-70b", "gemma-2-27b", "mistral-7b"] } ) print(response.json()) ```

You get back something like:

{
  "status": "ok",
  "data": {
    "responses": [
      {"model": "llama-3.1-70b", "text": "A grieving prince...", "ms": 412},
      {"model": "gemma-2-27b", "text": "Shakespeare's tragedy...", "ms": 387},
      {"model": "mistral-7b", "text": "Prince Hamlet...", "ms": 198}
    ]
  }
}

Perfect for evaluation harnesses and prompt engineering.