Multi-LLM RouterOne API key, every AI model
The Helix Multi-LLM Router API gives you OpenAI-compatible access to GPT-4, Claude, Gemini, Llama, Mistral, Qwen, and 50+ other models through one endpoint and one API key. Switch models with a single string change, compare outputs side-by-side, or set fallback chains for high availability.
- Free tier with 100 requests/month
- Fast, cached responses
- 99.9% uptime target
- Standard REST + JSON
Ask anything to start chatting… (sample responses)
What is the Multi-LLM Router API?
The Helix Multi-LLM Router API gives you OpenAI-compatible access to GPT-4, Claude, Gemini, Llama, Mistral, Qwen, and 50+ other models through one endpoint and one API key. Switch models with a single string change, compare outputs side-by-side, or set fallback chains for high availability.
How it works
- 1POST messages to /chat in OpenAI format — same shape you already use.
- 2Set `model` to any of 50+ supported names (gpt-4o, claude-3.5-sonnet, gemini-1.5-pro, llama-3.1-405b, etc.) or `auto` for cheapest/fastest routing.
- 3POST to /compare to send the same prompt to 3+ models and get a side-by-side response.
- 4Set `fallback_models` array — if the primary fails or times out, we try the next one transparently.
- 5Streaming, function calling, JSON mode, and vision are all supported via the same endpoint.
Endpoints
3 REST endpoints, all returning consistent JSON.
/chatSend chat completion request
/modelsList available models
/compareSame prompt to multiple models
Code in 5 languages
Copy and paste into your project. Replace YOUR_API_KEY with your RapidAPI key.
// Multi-LLM Router API
const response = await fetch(
"https://multi-llm-router-by-helix-api.p.rapidapi.com/chat",
{
method: "POST",
headers: {
"X-RapidAPI-Key": "YOUR_API_KEY",
"X-RapidAPI-Host": "multi-llm-router-by-helix-api.p.rapidapi.com",
"Content-Type": "application/json"
},
body: JSON.stringify({ "query": "your input" })
}
);
const data = await response.json();
console.log(data);What developers build with this API
Real use cases from production deployments.
Vendor Lock-in Insurance
Build your product against one stable API. Switch from GPT-4 to Claude overnight if pricing changes or quality regresses. No code rewrite.
Cost Optimization via Smart Routing
Route easy queries to GPT-4o-mini ($0.15/M tokens), reserve GPT-4o ($2.50/M) for hard problems. Auto-routing typically cuts costs 60-80% with no quality loss.
A/B Testing Models in Production
Send 50% of traffic to Claude, 50% to GPT-4. Compare user satisfaction, task completion, and costs in your own analytics.
Failover for High-Availability AI
OpenAI outages happen. Set `fallback_models: ['claude-3.5-sonnet', 'gemini-1.5-pro']` and your product never goes down.
Side-by-Side Comparison UIs
Build the next ChatGPT/Claude/Gemini comparison tool. /compare returns synchronized responses from N models in one request.
Pricing
All tiers include this API. No credit card for free tier.
BASIC
Free
- ✓ 100 reqs/month
- ✓ Hard limit
- ✓ All endpoints
PRO
$9.99/mo
- ✓ 10,000/month
- ✓ +$0.005 each
- ✓ All endpoints
ULTRA
$29.99/mo
- ✓ 100,000/month
- ✓ +$0.002 each
- ✓ All endpoints
MEGA
$99.99/mo
- ✓ 1,000,000/month
- ✓ +$0.001 each
- ✓ All endpoints
Frequently asked questions
Real answers to questions developers ask before integrating.