# Testing OpenRouter API: Free AI Model Access

> Source: <https://dev.to/ipsphil_digital/testing-openrouter-api-free-ai-model-access-2h5>
> Published: 2026-10-12 05:28:20+00:00

Learn how to test and use free AI models through OpenRouter's unified API.

`requests`: `pip install requests`

```
curl -X POST https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "google/gemini-2.0-flash-exp:free",
    "messages": [{"role": "user", "content": "Say hello in 3 languages"}]
  }'
python
import requests
import os

OPENROUTER_URL = "https://openrouter.ai/api/v1/chat/completions"

def test_openrouter(prompt: str, model: str = "google/gemini-2.0-flash-exp:free") -> str:
    """Test OpenRouter API with a prompt."""
    headers = {
        "Authorization": f"Bearer {os.getenv('OPENROUTER_API_KEY')}",
        "Content-Type": "application/json"
    }
    data = {
        "model": model,
        "messages": [{"role": "user", "content": prompt}],
        "temperature": 0.7,
        "max_tokens": 150
    }

    response = requests.post(OPENROUTER_URL, headers=headers, json=data, timeout=30)

    if response.status_code == 200:
        return response.json()["choices"][0]["message"]["content"]
    else:
        raise Exception(f"Error: {response.status_code} - {response.text}")

# Test it
if __name__ == "__main__":
    prompt = "Explain the difference between REST and GraphQL in 2 sentences"
    try:
        result = test_openrouter(prompt)
        print(f"Q: {prompt}")
        print(f"A: {result}")
    except Exception as e:
        print(f"Error: {e}")
```

OpenRouter offers many free models (look for `:free` suffix):

| Model | Best For | 
|---|---|
| `google/gemini-2.0-flash-exp:free` | General chat, coding | 
| `meta-llama/llama-3.1-8b-instruct:free` | Reasoning, analysis | 
| `mistralai/mistral-7b-instruct:free` | Fast responses | 
| `microsoft/phi-3-mini-128k-instruct:free` | Long context | 

OpenRouter provides a unified interface to dozens of free AI models. Perfect for testing, learning, and building AI-powered applications without API costs.