How to Implement Webhooks with Gemini API (Step by Step)

How to Implement Webhooks with Gemini API (Step by Step)

We’re building a webhook system using the Gemini API to catch real-time events that matter to your trading application. This matters because immediate responses to changes in your trading data can mean the difference between profit and loss. Miss one signal, and you might find yourself holding a bag of BTC when you should have sold.

Prerequisites

• Python 3.11+
• Pip for package management
• Flask 2.0+ for creating a simple server
• Gemini API Key and Secret
• Ngrok for testing webhook endpoints locally

Step 1: Setting Up Your Flask Server

First, you need a server to handle incoming webhook events. Flask is lightweight and easy to set up, making it a suitable choice.

from flask import Flask, request

app = Flask(__name__)

@app.route('/webhook', methods=['POST'])
def webhook():
 data = request.json
 print(data)
 return 'Webhook received', 200

if __name__ == '__main__':
 app.run(port=5000)

Here’s the thing: you can’t just run a Python script and expect it to receive webhooks. You gotta specify how your application behaves when it gets data. This snippet listens for POST requests at the /webhook endpoint and logs any incoming data. You’ll hit a 500 error if you forget to set up the route correctly, and trust me, I’ve been there. An unhandled exception will stop your server faster than you can say “debugger.”

Step 2: Installing Dependencies

Before you can fire up that Flask server, make sure you’ve installed the necessary libraries. Simply run:

pip install Flask requests

Missing libraries? Who hasn’t had a moment where a beautifully crafted piece of code threw a tantrum because it couldn’t find its best buddy? Common Python errors like “ModuleNotFoundError” will pop up if you skip this step.

Step 3: Exposing Your Local Server to the Internet

Just running Flask locally won’t cut it; you need to make it accessible for the Gemini API to send webhooks. Here’s where Ngrok enters the picture like a knight in shining armor. Install Ngrok and run:

ngrok http 5000

This command creates a tunnel to your local Flask app. You’ll get a public URL like http://abc123.ngrok.io. Use this URL to direct Gemini’s webhook events there. The first time you run this, you might miss configuring the port. If you do, you’ll just end up with confusing 404 errors that’ll have you questioning your existence.

Step 4: Registering Your Webhook with the Gemini API

You’ll need to tell the Gemini API where to send its webhook notifications. For this, execute a POST request via any API client or even curl:

curl -X POST 'https://api.gemini.com/v1/webhook' \
-H 'Content-Type: application/json' \
-H 'Gemini-API-Key: YOUR_API_KEY' \
-H 'Gemini-API-Signature: YOUR_API_SIGNATURE' \
-d '{"url":"http://abc123.ngrok.io/webhook", "event": "order.fill"}'

Make sure to replace YOUR_API_KEY and YOUR_API_SIGNATURE with your actual credentials. This tells Gemini to send order fill events to your Flask application. If you omit the event, you’ll get events you don’t want, like “order.canceled” that clutter your logs and might overload your system.

Step 5: Processing Incoming Webhook Data

Now that you’re set up to receive data, handle it inside your webhook function. Let’s add some logic to do something useful with this data. Update your Flask app:

from flask import Flask, request
import json

app = Flask(__name__)

@app.route('/webhook', methods=['POST'])
def webhook():
 data = request.json
 # Process the incoming data
 print(json.dumps(data, indent=4)) # For better readability
 return 'Webhook received', 200

if __name__ == '__main__':
 app.run(port=5000)

Here’s where things get interesting! You can act upon the data based on your application logic. (Pro tip: use tools like Postman to send test requests to your webhook URL. It’s way easier than trying to trigger actual trades just for testing.)

Step 6: Testing Your Webhook

The final piece to this puzzle is testing. Make sure your webhook generates proper responses by simulating events. Use Postman to send a POST request to your Ngrok URL:

curl -X POST 'http://abc123.ngrok.io/webhook' -H 'Content-Type: application/json' -d '{"example_key": "example_value"}'

This simulates an event sent by Gemini, allowing you to verify that everything is processed as expected. If you’re not seeing output as intended, check your server logs. I once spent a good hour debugging because I missed a typo in my JSON structure. Fun times.

The Gotchas

• Signature Verification: You can’t just trust incoming requests. Always verify signatures. Unverified data is dangerous, like letting strangers into your house while you’re on vacation.
• Rate Limits: Gemini has rate limits for API calls. Keep track of how many requests you’re sending, or you’ll get throttled during key events.
• Handling Duplicate Webhook Events: Gemini may send the same event multiple times. Your app needs to be idempotent – that is, it should handle duplicate events gracefully. Otherwise, you might end up with inflated balances or multiple orders.
• Localhost Limitations: Don’t forget that using Ngrok is just for testing. Eventually, you should move to a more permanent solution, like a dedicated server or cloud service.
• Security: Never expose sensitive data like API keys. Keep everything encrypted and secure.

Full Code

from flask import Flask, request
import json

app = Flask(__name__)

@app.route('/webhook', methods=['POST'])
def webhook():
 data = request.json
 print(json.dumps(data, indent=4)) # Process incoming data
 return 'Webhook received', 200

if __name__ == '__main__':
 app.run(port=5000)

What’s Next

Now that your webhook is set up and working, consider storing the incoming data in a database for later analysis or trade execution. It’s a small step that can unlock powerful insights.

FAQ

• Q: What should I do if my webhook isn’t receiving any data?
  A: First, confirm that your Flask server is running. Then check your Ngrok tunnel to see if it’s active. Lastly, look at your Gemini account settings to ensure there are no issues.
• Q: How can I test webhook functionality without making a real trade?
  A: Use tools like Postman or just run manual curl commands as shown in the earlier steps.
• Q: What should I do if I run into authentication issues with the Gemini API?
  A: Double-check your API key and signature. Ensure they’re generated correctly and have permissions for the actions you’re trying to perform.

Data Sources

• Gemini Webhook Documentation
• Flask Documentation

Last updated March 28, 2026. Data sourced from official docs and community benchmarks.

🕒 Published: March 28, 2026