Gemini API Tutorial via OpenRouter

This tutorial will guide you through using the Gemini API through OpenRouter's free endpoint. We'll cover setting up the request, making a simple completion call, and interpreting the response.

Prerequisites

  • An OpenRouter API key (obtainable from https://openrouter.ai)
  • Python 3.x
  • requests library (pip install requests)

Installation 

pip install requests

Example Code 

import requests API_KEY = "your_openrouter_api_key" ENDPOINT = "https://api.openrouter.ai/v1/chat/completions" def get_gemini_response(user_message): headers = { "Authorization": f"Bearer {API_KEY}", "Content-Type": "application/json" } payload = { "model": "google/gemini-2.0-flash-exp", "messages": [{"role": "user", "content": user_message}] } response = requests.post(ENDPOINT, json=payload, headers=headers) response.raise_for_status() return response.json()["choices"][0]["message"]["content"] if __name__ == "__main__": user_input = input("Ask Gemini: ") print("Gemini says:", get_gemini_response(user_input))

Explanation

  • Endpoint: https://api.openrouter.ai/v1/chat/completions is the unified endpoint used by OpenRouter to reach various LLM providers.
  • Model: We use google/gemini-2.0-flash-exp as an example; replace with any compatible model.
  • Headers: Authorization with Bearer token and Content-Type JSON.
  • Payload: The model field specifies which LLM to use, and messages contains the conversation history.

Running the Script

Save the script as gemini_tutorial.py and run:

python gemini_tutorial.py

Enter your message when prompted, and the script will display Gemini's response.

Tips

  • Use the free tier of OpenRouter to test without spending credits.
  • Adjust the model parameter to try different Gemini variants.
  • Handle rate limits by checking the response status code.

By following this tutorial, you'll be able to integrate Gemini into your applications using OpenRouter's API gateway.