My First Messenger Bot + Setup: Avoiding the Pitfalls I Fell Into

I’m diving into chatbots recently, so the next station was a Messenger bot. I thought I could just follow some steps with ChatGPT as my guide… but I missed one very important point.

👉 If you want to create a Messenger bot, you must have a business page under a BUSINESS type Meta app.

I didn’t know that. I was creating Meta apps and choosing anything but the right type—and that’s where the loop started.

Here’s the trap: once you create an app, you can never change its type. I went to the App Dashboard, tried to add Messenger under “Add Product”… but the magic button was gone.

I tried everything—different setups, endless searches, even trolling the web for answers. Nothing. Days passed.

And then I found the hidden treasure 🗝️:
When creating an app, you need to choose Other → Business. That’s it. If you miss this, Messenger will never show up as an option.

Here is the link where you can create a new app:
developers.facebook.com/apps

Once you start creating the app, in Use Cases choose Others

Then click Next and choose Business type

This is the magic I missed. After finding this, I could finally move forward! 🎉

Page Access Token

Next, you need to create a Page Access Token from Graph API Explorer
and make sure to select your business page—this is a MUST.

After that, you can add Messenger as a product in your app.

Also, set up a Verify Token (you can write your own). Be careful to save it somewhere safe and never share it.

Ngrok — The Local Tunnel

The journey is not finished here. Now you need ngrok. When you run your bot locally, Facebook cannot reach localhost. Ngrok creates a secure HTTPS tunnel to your machine so Messenger can communicate with your bot.

How to install ngrok

1. - Download from ngrok.com
2. - Unzip/Install it
3. - Authenticate once with your ngrok account:

ngrok config add-authtoken YOUR_AUTH_TOKEN

After running your bot script

from flask import Flask, request
import requests
import json

app = Flask(__name__)

PAGE_ACCESS_TOKEN = "PAGE_ACCESS_TOKEN"
VERIFY_TOKEN = "VERIFY_TOKEN"

# The bot will look for an exact, case-insensitive match.
# Add or remove questions and answers as needed.
qa_database = {
    "hello": "Hello! I am messenger bot and I am under development. Can't answer any questions yet.",
}

# --- Root route for testing ---
@app.route("/", methods=["GET"])
def home():
    return "Messenger bot is running!"

# --- Webhook route for Facebook ---
@app.route("/webhook", methods=["GET", "POST"])
def webhook():
    if request.method == "GET":
        # Verification handshake
        token_sent = request.args.get("hub.verify_token")
        return verify_fb_token(token_sent)
    else:
        # Handle messages
        output = request.get_json()
        for event in output.get("entry", []):
            for messaging_event in event.get("messaging", []):
                sender_id = messaging_event["sender"]["id"]
                if messaging_event.get("message"):
                    message_text = messaging_event["message"].get("text")
                    if message_text:
                        # Convert message to lowercase for case-insensitive matching
                        message_text_lower = message_text.lower().strip()

                        # Look for a response in the QA database
                        response_text = qa_database.get(message_text_lower)

                        if response_text:
                            send_message(sender_id, response_text)
                        else:
                            # Default response if no match is found
                            default_response = "I'm sorry, I don't understand that question. You can try asking one of the following:\n\n"
                            # List all available questions
                            for q in qa_database.keys():
                                default_response += f"- {q}\n"
                            send_message(sender_id, default_response)
        return "Message Processed", 200

def verify_fb_token(token_sent):
    if token_sent == VERIFY_TOKEN:
        return request.args.get("hub.challenge")
    return "Invalid verification token"

def send_message(recipient_id, text):
    """Send message back to Facebook Messenger user"""
    url = "https://graph.facebook.com/v21.0/me/messages"
    params = {"access_token": PAGE_ACCESS_TOKEN}
    headers = {"Content-Type": "application/json"}
    data = {
        "recipient": {"id": recipient_id},
        "message": {"text": text}
    }
    response = requests.post(url, params=params, headers=headers, json=data)
    if response.status_code != 200:
        print(f"Error sending message: {response.text}")

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

press the link bellow and you will see Bot is running!

Now open a new terminal and type:

ngrok http 5000

You will get a link like:

https://qwerty123.ngrok-free.app/

Paste the URL into Meta App Dashboard → Messenger → Webhooks like this:

https://qwerty123.ngrok-free.app/webhook

then press Verify and press button.

⚠️ If you’re using the free version of ngrok, the link changes every time you restart it. That means you’ll need to update the Callback URL in your Meta App every time you run your bot.

💡 Tip: For testing, I saved all my tokens in a separate file config.py and imported them in my bot script:

# config.py
VERIFY_TOKEN = "my_secret_token"
PAGE_ACCESS_TOKEN = "your_page_access_token_here"

Then in your main bot code:

from config import VERIFY_TOKEN, PAGE_ACCESS_TOKEN

This keeps your tokens out of the main script, making it safer and easier to manage.

Key Takeaways:

• Small setup mistakes can cost days.
• Planning is crucial.
• Keep your tokens safe.
• Use ngrok for local testing.
• Double-check your app types.