Call Tracking with Node.js and Express

This Express.js application uses Twilio to track the effectiveness of different marketing channels by purchasing phone numbers from Twilio, forwarding incoming calls to a salesperson, and displaying charts showing data about the phone numbers and calls they receive. The application has three main features: searching for available phone numbers, buying phone numbers, and displaying statistics on lead sources and cities. The client-side JavaScript application fetches call tracking statistics in JSON from the server using jQuery and displays them in colorful pie charts created with Chart.js.