Testing OpenRouter API: Free AI Model Access

A developer demonstrated how to call OpenRouter's unified chat completions API to access free AI models, providing a Python function and curl example that authenticate with an API key and target models tagged with the ':free' suffix. The walkthrough lists several no-cost options, including Google's gemini-2.0-flash-exp, Meta's llama-3.1-8b-instruct, Mistral's mistral-7b-instruct, and Microsoft's phi-3-mini-128k-instruct, positioning the service as a way to test and build AI applications without API costs.

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.