QuickstartSMSPython

Receiving SMS Messages

Prerequisites

Before proceeding, ensure you have obtained a phone number and API key as described in the prerequisites.

Installation

Create a Python virtual environment:

$python3 -m venv venv

Activate the virtual environment:

$source venv/bin/activate

Install the Pinnacle Python SDK and FastAPI:

$pip install rcs "fastapi[standard]"

This guide uses version rcs>=2.0.4. Requires: Python <4.0, >=3.8

Configuration

Create an .env file in your project root and add your Pinnacle API key and signing secret:

PINNACLE_API_KEY="your_api_key" # pnclk_
SENDER_NUMBER="your_phone_number" # +12345678910
PINNACLE_SIGNING_SECRET="your_signing_secret" # pss_

Setting Up a Webhook

To receive inbound SMS messages, you need to configure a webhook in the Pinnacle dashboard:

  1. Navigate to Development > Webhooks in the Pinnacle dashboard

  2. Click Create new webhook

  3. Give your webhook a descriptive name

  4. Enter your webhook endpoint URL

    • For local development, use an ngrok tunnel pointing to localhost:8000/inbound-sms
    • For production, use your deployed server URL

  5. After creation, copy the signing secret and add it to your .env file

  6. Attach a phone number to your webhook to receive messages. If the number is a sandbox number, ensure that you’ve whitelisted a number and verified the 4 digit PIN.

    through the phone icon on the sandbox number’s card.

Creating Your Webhook Endpoint

Create a new Python file (e.g., main.py) and add the following snippet to the right.

The code above creates a FastAPI endpoint that:

  • Receives webhook POST requests at /inbound-sms
  • Verifies the webhook signature using your signing secret
  • Processes incoming message events
  • Handles both received messages and message status updates

Running Your Server

Start the FastAPI server:

$fastapi dev main.py

Your server will start on http://localhost:8000. If you’re using ngrok for local development, start it in a separate terminal:

$ngrok http 8000

Use the ngrok URL (e.g., https://abc123.ngrok.io/inbound-sms) as your webhook endpoint in the Pinnacle dashboard.

Testing Your Webhook

Send an SMS to your Pinnacle phone number from any mobile device. You should see the message logged in your server console:

Received message from +14155551234: Hello, this is a test!

If you’re not receiving any messages, make sure you have a phone number associated with your webhook.

Your webhook should now be successfully receiving inbound SMS messages as well message status updates for outbound messages!

For more detail about processing the message payload received, please view the process method.

Optionally, you can also create the /send-sms/{phone_number} endpoint to send an initial SMS message out.