> ## Documentation Index > Fetch the complete documentation index at: https://plivo.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Number Masking > Hide caller and recipient phone numbers using proxy number masking ## Overview Phone number masking hides the phone numbers of parties in a call from each other. Many businesses find it advantageous to anonymize communication between two parties — for example, between a customer and a delivery agent on a food delivery service platform or a driver and a rider using a ride-hailing application. Businesses can implement phone number masking by sending calls through an intermediate phone number that acts as a proxy between the two parties. A Plivo number can serve as the intermediate number to connect the two parties while keeping their contact information private. ## How it works As an example, we’ll build a number-masking application for a food delivery service that lets the company connect customers with delivery agents and vice versa without revealing any actual phone numbers. To do this, you 1. Create a customer-to-agent phone number mapping in your application’s back end. 2. Create the number masking application using Plivo. 3. Assign the number masking application to a Plivo number. ## Prerequisites To get started, you need a Plivo account — [sign up](https://cx.plivo.com/signup) with your work email address if you don’t have one already. You must have a voice-enabled Plivo phone number to receive incoming calls; you can rent numbers from the [Numbers](https://cx.plivo.com/phone-numbers) page of the Plivo console, or by using the [Numbers API](/numbers/). If this is your first time using Plivo APIs, follow our instructions to [set up a Node.js development environment](/sdk/server/set-up-node-dev-environment-api-xml-voice/) and a web server and safely expose that server to the internet. ## Create a 1:1 map with actual numbers Create customer-to-agent phone number mapping for the application. Whenever a customer places an order, their phone number should be stored in a database for your application to access. A delivery agent will be assigned for the order, and the agent’s number will also be stored in your database, and will be mapped to the customer's number: ``` Customer’s Number <-> Agent’s Number 1-415-666-7777 1-415-666-7778 ``` We created sample mapping data in a config.js file: ```javascript theme={null} const config = {app: {port: 5000}} config.customerAgentMap = { '14156667777':'14156667778', '14156667779':'14156667780', '14156667781':'14156667782' }; module.exports = config; ``` ## Create an Express application for number masking Create a file called `number_masking.js` and paste into it this code. ```js theme={null} const config = require('./config'); const plivo = require('plivo'); const express = require('express'); const app = express(); app.set('port', (process.env.PORT || 5000)); // Handle incoming calls to a Plivo number, connect agent with customer and vice versa without revealing their actual phone numbers. app.all('/handleincoming/', function(req, res) { const fromNumber = (req.query.From); const toNumber = (req.query.To); const response = plivo.Response(); const customerPhoneMapping = config.customerAgentMap; const agentCustomerMapping = Object.fromEntries(Object.entries(customerPhoneMapping).map(v => v.reverse())); if(fromNumber in customerPhoneMapping){ // Check whether the customer's number is in the customer-agent mapping const number = customerPhoneMapping[fromNumber]; // Assign the value from the customer-agent array to number variable const params = { 'callerId': toNumber, // Plivo number is used as the caller ID for the call toward the agent }; const dial = response.addDial(params); const destNumber = number; dial.addNumber(destNumber); res.send(response.toXML()); } else if(fromNumber in agentCustomerMapping){ // Check whether the agent's number is in the customer-agent mapping const number = agentCustomerMapping[fromNumber]; // Assign the key from the customer-agent array to number variable const params = { 'callerId': toNumber, // Plivo number is used as the caller ID for the call toward the customer }; const dial = response.addDial(params); const destNumber = number; dial.addNumber(destNumber); res.send(response.toXML()); } }); app.listen(app.get('port'), function () { console.log('Node app is running on port', app.get('port')); }); ``` Save the file and run it. ```shell theme={null} $ node number_masking.js ``` You should see your basic server application in action at [http://localhost:5000/handleincoming/](http://localhost:5000/handleincoming/). [Set up ngrok](/sdk/server/set-up-node-dev-environment-api-xml-voice/#ngrok-setup) to expose your local server to the internet. Now people can call your Plivo number. If an incoming call to your Plivo number is from one of the customer phone numbers in the customer-agent map — for example, if the caller number is `14156667777` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. If the incoming call to your Plivo number is from one of the agent phone numbers in the customer-agent map — for example, if the caller number is `14156667778` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. ## Create a Plivo application Associate the Express application you created with Plivo by creating a Plivo application. Visit Voice > [Applications](https://cx.plivo.com/xml-applications) in the Plivo console and click on **Add New Application**, or use Plivo’s [Application API](/account/api/application/#create-an-application). Give your application a name — we called ours `Number Masking`. Enter the server URL you want to use (for example, https\://\.ngrok.io/handleincoming/) in the `Answer URL` field and set the method as `GET`. Click **Create Application** to save your application. ## Assign a Plivo number to your application Navigate to the [Numbers](https://cx.plivo.com/phone-numbers) page and select the phone number you want to use for this application. From the Application Type drop-down, select `XML Application`. From the Plivo Application drop-down, select `Number Masking` (the name we gave the application). Click **Update Number** to save. ## Test To test the application, you need two Plivo numbers. Set up one of your numbers as a customer and another as an agent in the customer-to-agent mapping data in the config file. Make a call from each of your mobile numbers to the Plivo number you mapped to the application. You should see that the call is forwarded to the other number, and that the incoming call has the Plivo number as the caller ID. ## Overview Phone number masking hides the phone numbers of parties in a call from each other. Many businesses find it advantageous to anonymize communication between two parties — for example, between a customer and a delivery agent on a food delivery service platform or a driver and a rider using a ride-hailing application. Businesses can implement phone number masking by sending calls through an intermediate phone number that acts as a proxy between the two parties. A Plivo number can serve as the intermediate number to connect the two parties while keeping their contact information private. ## Outline As an example, we’ll build a number-masking application for a food delivery service that lets the company connect customers with delivery agents and vice versa without revealing any actual phone numbers. To do this, you 1. Create a customer-to-agent phone number mapping in your application’s back end. 2. Create the number masking application using Plivo. 3. Assign the number masking application to a Plivo number. ## Prerequisites To get started, you need a Plivo account — [sign up](https://cx.plivo.com/signup) with your work email address if you don’t have one already. You must have a voice-enabled Plivo phone number to receive incoming calls; you can rent numbers from the [Numbers](https://cx.plivo.com/phone-numbers) page of the Plivo console, or by using the [Numbers API](/numbers/). If this is your first time using Plivo APIs, follow our instructions to [set up a Ruby development environment](/sdk/server/set-up-ruby-dev-environment-api-xml-voice/) and a web server and safely expose that server to the internet. ## Create a 1:1 map with actual numbers Create customer-to-agent phone number mapping for the application. Whenever a customer places an order, their phone number should be stored in a database for your application to access. A delivery agent will be assigned for the order, and the agent’s number will also be stored in your database, and will be mapped to the customer's number: ``` Customer’s Number <-> Agent’s Number 1-415-666-7777 1-415-666-7778 ``` We created sample mapping data in a config/application.rb file: ``` # customer <> agent map config.base_map = {"14156667777" => "14156667778", "14156667779" => "14156667780", "14156667781" => "14156667782"} ``` ## Create a Rails controller for number masking Change to the project directory and run the command `rails generate controller Numbermasking` to create a Rails controller named numbermasking\_controller in the app/controllers/ directory. Edit the app/controllers/numbermasking\_controller.rb file and paste into it this code: ```ruby theme={null} include Plivo include Plivo::XML include Plivo::Exceptions \# Handle incoming calls to a Plivo number, connect agent with customer and vice versa without revealing their actual phone numbers. class NumbermaskingController < ApplicationController def handle_incoming customer_agent_map = Rails.application.config.base_map agent_customer_map = customer_agent_map.invert from_number = params[:From] to_number = params[:To] response = Response.new() customer_to_agent = customer_agent_map.include?(from_number) # Check whether the customer's number is in the customer-agent mapping agent_to_customer = agent_customer_map.include?(from_number) # Check whether the agent's number is in the customer-agent mapping if(customer_to_agent == true) dest_number = customer_agent_map[from_number] # Assign the value from the customer-agent array to dest_number variable params = { 'callerId' => to_number # Plivo number is used as the caller ID for the call toward the agent } dial = response.addDial(params) dial.addNumber(dest_number) elsif(agent_to_customer == true) dest_number = agent_customer_map[from_number] # Assign the key from the customer-agent array to dest_number variable params = { 'callerId' => to_number # Plivo number is used as the caller ID for the call toward the customer } dial = response.addDial(params) dial.addNumber(dest_number) end xml = PlivoXML.new(response) puts xml.to_xml() render xml: xml.to_xml end end ``` ### Add a route Add a route for the handle\_incoming function in NumbermaskingController class. Edit the config/routes.rb file and add this line after the outbound route: ```shell theme={null} get 'numbermasking/handle_incoming' ``` Start the Rails server to forward incoming calls. ```shell theme={null} $ rails server ``` You should see your basic server application in action at [http://localhost:3000/numbermasking/handle\_incoming/](http://localhost:3000/numbermasking/handle_incoming/). [Set up ngrok](/sdk/server/set-up-ruby-dev-environment-api-xml-voice/#ngrok-setup) to expose your local server to the internet.
Note: Before you start the ngrok service, add ngrok in the config.hosts list in the config/environments/development.rb file and include the line below. You’ll start to see Blocked host errors if you fail to add this.
```shell theme={null} # Whitelist ngrok domain config.hosts << /[a-z0-9]+\.ngrok\.io/ ``` Now people can call your Plivo number. If an incoming call to your Plivo number is from one of the customer phone numbers in the customer-agent map — for example, if the caller number is `14156667777` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. If the incoming call to your Plivo number is from one of the agent phone numbers in the customer-agent map — for example, if the caller number is `14156667778` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. ## Create a Plivo application Associate the Rails controller you created with Plivo by creating a Plivo application. Visit Voice > [Applications](https://cx.plivo.com/xml-applications) in the Plivo console and click on **Add New Application**, or use Plivo’s [Application API](/account/api/application/#create-an-application). Give your application a name — we called ours `Number Masking`. Enter the server URL you want to use (for example, https\://\.ngrok.io/handleincoming/) in the `Answer URL` field and set the method as `GET`. Click **Create Application** to save your application. ## Assign a Plivo number to your application Navigate to the [Numbers](https://cx.plivo.com/phone-numbers) page and select the phone number you want to use for this application. From the Application Type drop-down, select `XML Application`. From the Plivo Application drop-down, select `Number Masking` (the name we gave the application). Click **Update Number** to save. ## Test To test the application, you need two Plivo numbers. Set up one of your numbers as a customer and another as an agent in the customer-to-agent mapping data in the config file. Make a call from each of your mobile numbers to the Plivo number you mapped to the application. You should see that the call is forwarded to the other number, and that the incoming call has the Plivo number as the caller ID. ## Overview Phone number masking hides the phone numbers of parties in a call from each other. Many businesses find it advantageous to anonymize communication between two parties — for example, between a customer and a delivery agent on a food delivery service platform or a driver and a rider using a ride-hailing application. Businesses can implement phone number masking by sending calls through an intermediate phone number that acts as a proxy between the two parties. A Plivo number can serve as the intermediate number to connect the two parties while keeping their contact information private. ## How it works As an example, we’ll build a number-masking application for a food delivery service that lets the company connect customers with delivery agents and vice versa without revealing any actual phone numbers. To do this, you 1. Create a customer-to-agent phone number mapping in your application’s back end. 2. Create the number masking application using Plivo. 3. Assign the number masking application to a Plivo number. ## Prerequisites To get started, you need a Plivo account — [sign up](https://cx.plivo.com/signup) with your work email address if you don’t have one already. You must have a voice-enabled Plivo phone number to receive incoming calls; you can rent numbers from the [Numbers](https://cx.plivo.com/phone-numbers) page of the Plivo console, or by using the [Numbers API](/numbers/). If this is your first time using Plivo APIs, follow our instructions to [set up a Python development environment](/sdk/server/set-up-python-dev-environment-api-xml-voice/) and a web server and safely expose that server to the internet. ## Create a 1:1 map with actual numbers Create customer-to-agent phone number mapping for the application. Whenever a customer places an order, their phone number should be stored in a database for your application to access. A delivery agent will be assigned for the order, and the agent’s number will also be stored in your database, and will be mapped to the customer's number: ``` Customer’s Number <-> Agent’s Number 1-415-666-7777 1-415-666-7778 ``` We created sample mapping data in a config.ini file: ``` [c2amap] customer_agent = {"14156667777":"14156667778", "14156667779":"14156667780", "14156667781":"14156667782"} ``` ## Create a Flask application for number masking Create a file called `number_masking.py` and paste into it this code. ```py theme={null} import json from flask import Flask, Response, request from configparser import ConfigParser from plivo import plivoxml config = ConfigParser() config.read('config.ini') app = Flask(__name__) \# Handle incoming calls to a Plivo number, connect agent with customer and vice versa without revealing their actual phone numbers. @app.route("/handleincoming/", methods=["GET", "POST"]) def number_masking(): base_map = config.get("c2amap","customer_agent") customer_agent_map = json.loads(base_map) # Customer-agent mapping data agent_customer_map = {v: k for k, v in customer_agent_map.items()} # Agent-customer mapping data from_number = request.form.get("From") or request.args.get("From") to_number = request.form.get("To") or request.args.get("To") response = plivoxml.ResponseElement() if from_number in customer_agent_map: # Check whether the customer's number is in the customer-agent mapping number = customer_agent_map[from_number] # Assign the value from the customer-agent array to number variable response.add( plivoxml.DialElement( caller_id=to_number, # Plivo number is used as the caller ID for the call toward the agent ).add(plivoxml.NumberElement(number)) ) elif from_number in agent_customer_map: # Check whether the agent's number is in the customer-agent mapping number = agent_customer_map[from_number] # Assign the key from the customer-agent array to number variable response.add( plivoxml.DialElement( caller_id=to_number, # Plivo number is used as the caller ID for the call toward the customer ).add(plivoxml.NumberElement(number)) ) print(response) return Response(response.to_string(), mimetype='application/xml') if __name__ == "__main__": app.run(host="0.0.0.0", debug=True) ``` Save the file and run it. ```shell theme={null} $ python number_masking.py ``` You should see your basic server application in action at [http://localhost:5000/handleincoming/](http://localhost:5000/handleincoming/). [Set up ngrok](/sdk/server/set-up-python-dev-environment-api-xml-voice/#ngrok-setup) to expose your local server to the internet. Now people can call your Plivo number. If an incoming call to your Plivo number is from one of the customer phone numbers in the customer-agent map — for example, if the caller number is `14156667777` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. If the incoming call to your Plivo number is from one of the agent phone numbers in the customer-agent map — for example, if the caller number is `14156667778` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. ## Create a Plivo application Associate the Flask application you created with Plivo by creating a Plivo application. Visit Voice > [Applications](https://cx.plivo.com/xml-applications) in the Plivo console and click on **Add New Application**, or use Plivo’s [Application API](/account/api/application/#create-an-application). Give your application a name — we called ours `Number Masking`. Enter the server URL you want to use (for example, https\://\.ngrok.io/handleincoming/) in the `Answer URL` field and set the method as `GET`. Click **Create Application** to save your application. ## Assign a Plivo number to your application Navigate to the [Numbers](https://cx.plivo.com/phone-numbers) page and select the phone number you want to use for this application. From the Application Type drop-down, select `XML Application`. From the Plivo Application drop-down, select `Number Masking` (the name we gave the application). Click **Update Number** to save. ## Test To test the application, you need two Plivo numbers. Set up one of your numbers as a customer and another as an agent in the customer-to-agent mapping data in the config file. Make a call from each of your mobile numbers to the Plivo number you mapped to the application. You should see that the call is forwarded to the other number, and that the incoming call has the Plivo number as the caller ID. ## Overview Phone number masking hides the phone numbers of parties in a call from each other. Many businesses find it advantageous to anonymize communication between two parties — for example, between a customer and a delivery agent on a food delivery service platform or a driver and a rider using a ride-hailing application. Businesses can implement phone number masking by sending calls through an intermediate phone number that acts as a proxy between the two parties. A Plivo number can serve as the intermediate number to connect the two parties while keeping their contact information private. ## How it works As an example, we’ll build a number-masking application for a food delivery service that lets the company connect customers with delivery agents and vice versa without revealing any actual phone numbers. To do this, you 1. Create a customer-to-agent phone number mapping in your application’s back end. 2. Create the number masking application using Plivo. 3. Assign the number masking application to a Plivo number. ## Prerequisites To get started, you need a Plivo account — [sign up](https://cx.plivo.com/signup) with your work email address if you don’t have one already. You must have a voice-enabled Plivo phone number to receive incoming calls; you can rent numbers from the [Numbers](https://cx.plivo.com/phone-numbers) page of the Plivo console, or by using the [Numbers API](/numbers/). If this is your first time using Plivo APIs, follow our instructions to [set up a PHP development environment](/sdk/server/set-up-php-dev-environment-api-xml-voice/) and a web server and safely expose that server to the internet. ## Create a 1:1 map with actual numbers Create customer-to-agent phone number mapping for the application. Whenever a customer places an order, their phone number should be stored in a database for your application to access. A delivery agent will be assigned for the order, and the agent’s number will also be stored in your database, and will be mapped to the customer's number: ``` Customer’s Number <-> Agent’s Number 1-415-666-7777 1-415-666-7778 ``` We created sample mapping data in a config/app.php file: ```php theme={null} 'customer_agent_map' => [ '14156667777' => '14156667778', '14156667779' => '14156667780', '14156667781' => '14156667782', ], ``` ## Create a Laravel controller for number masking Change to the project directory and run this command to create a Laravel controller for inbound calls. ```shell theme={null} $ php artisan make:controller MaskingController ``` This command generates a controller named MaskingController in the app/http/controllers/ directory. Edit the app/http/controllers/MaskingController.php file and paste into it this code: ```php theme={null} $to_number, // Plivo number is used as the caller ID for the call toward the agent ); $dial = $response->addDial($params); $dial->addNumber($number); } elseif ($agent_to_customer == true){ $number = array_search($from_number, $customerPhoneMaping); // Assign the key from the customer-agent array to $number variable $params = array( 'callerId' => $to_number, // Plivo number is used as the caller ID for the call toward the customer ); $dial = $response->addDial($params); $dial->addNumber($number); } $xml_response = $response->toXML(); return response($xml_response, 200)->header('Content-Type', 'application/xml'); } } ``` ### Add a route To add a route for the functions in the MaskingController class, edit the routes/web.php file and add this line at the end of the file: ```shell theme={null} Route::match(['get', 'post'], '/numbermasking', 'App\Http\Controllers\MaskingController@numberMasking'); ``` Note: You can edit the app/Http/Middleware/VerifyCsrfToken.php file and add the route of the app numbermasking to the “except” array to disable CSRF verification. Run this command to start the Laravel server to forward incoming calls. ```shell theme={null} $ php artisan serve ``` You should see the Laravel controller in action on [http://localhost:8000/numbermasking/](http://localhost:8000/numbermasking/). [Set up ngrok](/sdk/server/set-up-php-dev-environment-api-xml-voice/#ngrok-setup) to expose your local server to the internet. Now people can call your Plivo number. If an incoming call to your Plivo number is from one of the customer phone numbers in the customer-agent map — for example, if the caller number is `14156667777` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. If the incoming call to your Plivo number is from one of the agent phone numbers in the customer-agent map — for example, if the caller number is `14156667778` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. ## Create a Plivo application Associate the Laravel controller you created with Plivo by creating a Plivo application. Visit Voice > [Applications](https://cx.plivo.com/xml-applications) in the Plivo console and click on **Add New Application**, or use Plivo’s [Application API](/account/api/application/#create-an-application). Give your application a name — we called ours `Number Masking`. Enter the server URL you want to use (for example, https\://\.ngrok.io/handleincoming/) in the `Answer URL` field and set the method as `GET`. Click **Create Application** to save your application. ## Assign a Plivo number to your application Navigate to the [Numbers](https://cx.plivo.com/phone-numbers) page and select the phone number you want to use for this application. From the Application Type drop-down, select `XML Application`. From the Plivo Application drop-down, select `Number Masking` (the name we gave the application). Click **Update Number** to save. ## Test To test the application, you need two Plivo numbers. Set up one of your numbers as a customer and another as an agent in the customer-to-agent mapping data in the config file. Make a call from each of your mobile numbers to the Plivo number you mapped to the application. You should see that the call is forwarded to the other number, and that the incoming call has the Plivo number as the caller ID. ## Overview Phone number masking hides the phone numbers of parties in a call from each other. Many businesses find it advantageous to anonymize communication between two parties — for example, between a customer and a delivery agent on a food delivery service platform or a driver and a rider using a ride-hailing application. Businesses can implement phone number masking by sending calls through an intermediate phone number that acts as a proxy between the two parties. A Plivo number can serve as the intermediate number to connect the two parties while keeping their contact information private. ## How it works As an example, we’ll build a number-masking application for a food delivery service that lets the company connect customers with delivery agents and vice versa without revealing any actual phone numbers. To do this, you 1. Create a customer-to-agent phone number mapping in your application’s back end. 2. Create the number masking application using Plivo. 3. Assign the number masking application to a Plivo number. ## Prerequisites To get started, you need a Plivo account — [sign up](https://cx.plivo.com/signup) with your work email address if you don’t have one already. You must have a voice-enabled Plivo phone number to receive incoming calls; you can rent numbers from the [Numbers](https://cx.plivo.com/phone-numbers) page of the Plivo console, or by using the [Numbers API](/numbers/). If this is your first time using Plivo APIs, follow our instructions to [set up a .NET development environment](/sdk/server/set-up-dotnet-dev-environment-api-xml-voice/) and a web server and safely expose that server to the internet. ## Create a 1:1 map with actual numbers Create customer-to-agent phone number mapping for the application. Whenever a customer places an order, their phone number should be stored in a database for your application to access. A delivery agent will be assigned for the order, and the agent’s number will also be stored in your database, and will be mapped to the customer's number: ``` Customer’s Number <-> Agent’s Number 1-415-666-7777 1-415-666-7778 ``` We created an App.config file with sample mapping data for this project: ```xml theme={null}
``` ## Create an MVC controller for number masking In Visual Studio, navigate to the Controllers directory in the NumberMasking application. Create a controller named `HandleIncomingController.cs` and paste into it this code: ```cs theme={null} using System.Configuration; using Plivo.XML; using System.Collections.Generic; using System.Linq; using Microsoft.AspNetCore.Mvc; using System.Diagnostics; using System.Collections; // Handle incoming calls to a Plivo number, connect agent with customer and vice versa without revealing their actual phone numbers. namespace NumberMasking.Controllers { public class HandleIncomingController : Controller { // GET: // public IActionResult Index() { string FromNumber = Request.Query["From"]; string ToNumber = Request.Query["To"]; var resp = new Response(); // Customer-agent mapping var CustomerAgentMap = (ConfigurationManager.GetSection("CustomerAgent") as Hashtable) .Cast() .ToDictionary(n => n.Key.ToString(), n => n.Value.ToString()); // Agent-customer mapping var AgentCustomerMap = CustomerAgentMap.ToDictionary(kp => kp.Value, kp => kp.Key); if (CustomerAgentMap.ContainsKey(FromNumber)) // Check whether the customer's number is in the customer-agent mapping { var DestNumber = CustomerAgentMap[FromNumber]; // Assign the value from the customer-agent array to number variable Dial dial = new Dial(new Dictionary() { {"callerId", ToNumber} // Plivo number is used as the caller ID for the call toward the agent }); dial.AddNumber(DestNumber, new Dictionary() { }); resp.Add(dial); } else if (AgentCustomerMap.ContainsKey(FromNumber)) // Check whether the agent's number is in the customer-agent mapping { var DestNumber = AgentCustomerMap[FromNumber]; // Assign the key from the customer-agent array to number variable Dial dial = new Dial(new Dictionary() { {"callerId", ToNumber} // Plivo number is used as the caller ID for the call toward the customer }); dial.AddNumber(DestNumber, new Dictionary() { }); resp.Add(dial); } Debug.WriteLine(resp.ToString()); var output = resp.ToString(); return this.Content(output, "text/xml"); } } } ``` Before you start the application, edit the Properties/launchSettings.json file and set the `applicationUrl`: ```json theme={null} "applicationUrl": "http://localhost:5000/" ``` Run the project and you should see your basic server application in action at [http://localhost:5000/handleincoming/](http://localhost:5000/handleincoming/). [Set up ngrok](/sdk/server/set-up-dotnet-dev-environment-api-xml-voice/#ngrok-setup) to expose your local server to the internet. Now people can call your Plivo number. If an incoming call to your Plivo number is from one of the customer phone numbers in the customer-agent map — for example, if the caller number is `14156667777` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. If the incoming call to your Plivo number is from one of the agent phone numbers in the customer-agent map — for example, if the caller number is `14156667778` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. ## Create a Plivo application Associate the MVC controller you created with Plivo by creating a Plivo application. Visit Voice > [Applications](https://cx.plivo.com/xml-applications) in the Plivo console and click on **Add New Application**, or use Plivo’s [Application API](/account/api/application/#create-an-application). Give your application a name — we called ours `Number Masking`. Enter the server URL you want to use (for example, https\://\.ngrok.io/handleincoming/) in the `Answer URL` field and set the method as `GET`. Click **Create Application** to save your application. ## Assign a Plivo number to your application Navigate to the [Numbers](https://cx.plivo.com/phone-numbers) page and select the phone number you want to use for this application. From the Application Type drop-down, select `XML Application`. From the Plivo Application drop-down, select `Number Masking` (the name we gave the application). Click **Update Number** to save. ## Test To test the application, you need two Plivo numbers. Set up one of your numbers as a customer and another as an agent in the customer-to-agent mapping data in the config file. Make a call from each of your mobile numbers to the Plivo number you mapped to the application. You should see that the call is forwarded to the other number, and that the incoming call has the Plivo number as the caller ID. ## Overview Phone number masking hides the phone numbers of parties in a call from each other. Many businesses find it advantageous to anonymize communication between two parties — for example, between a customer and a delivery agent on a food delivery service platform or a driver and a rider using a ride-hailing application. Businesses can implement phone number masking by sending calls through an intermediate phone number that acts as a proxy between the two parties. A Plivo number can serve as the intermediate number to connect the two parties while keeping their contact information private. ## How it works As an example, we’ll build a number-masking application for a food delivery service that lets the company connect customers with delivery agents and vice versa without revealing any actual phone numbers. To do this, you 1. Create a customer-to-agent phone number mapping in your application’s back end. 2. Create the number masking application using Plivo. 3. Assign the number masking application to a Plivo number. ## Prerequisites To get started, you need a Plivo account — [sign up](https://cx.plivo.com/signup) with your work email address if you don’t have one already. You must have a voice-enabled Plivo phone number to receive incoming calls; you can rent numbers from the [Numbers](https://cx.plivo.com/phone-numbers) page of the Plivo console, or by using the [Numbers API](/numbers/). If this is your first time using Plivo APIs, follow our instructions to [set up a Java development environment](/sdk/server/set-up-java-dev-environment-api-xml-voice/) and a web server and safely expose that server to the internet. ## Create a 1:1 map with actual numbers Create customer-to-agent phone number mapping for the application. Whenever a customer places an order, their phone number should be stored in a database for your application to access. A delivery agent will be assigned for the order, and the agent’s number will also be stored in your database, and will be mapped to the customer's number: ``` Customer's Number <-> Agent's Number 1-415-666-7777 1-415-666-7778 ``` We created sample mapping data in the src/main/resources/application.properties file: ```json theme={null} spring.main.banner-mode=off spring.output.ansi.enabled=ALWAYS logging.pattern.console=%clr(%d{yy-MM-dd E HH:mm:ss.SSS}){blue} %clr(%-5p) %clr(%logger{0}){blue} %clr(%m){faint}%n number.map={"14156667777":"14156667778", "14156667779":"14156667780", "14156667781":"14156667782"} ``` ## Create a Spring application for number masking Open the NumberMaskingApplication.java file in the src/main/java/com.example.NumberMasking/ folder and paste into it this code. Note: Here, the demo application name is NumberMaskingApplication.java because the friendly name we provided in Spring Initializr was `NumberMasking`. ```java theme={null} package com.example.NumberMasking; import com.plivo.api.exceptions.PlivoXmlException; import com.plivo.api.xml.Dial; import com.plivo.api.xml.Response; import com.plivo.api.xml.Number; import org.springframework.beans.factory.annotation.Value; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.web.bind.annotation.*; import com.google.common.collect.HashBiMap; import java.util.Map; @SpringBootApplication @RestController public class NumberMaskingApplication { @Value("#{${number.map}}") Map CustomerAgentMap; public static void main(String[] args) { SpringApplication.run(NumberMaskingApplication.class, args); } // Handle incoming calls to a Plivo number, connect agent with customer and vice versa without revealing their actual phone numbers. @RequestMapping(value = "/number_masking/", produces = { "application/xml" }, method = { RequestMethod.GET, RequestMethod.POST }) public Response HandleIncoming(@RequestParam("From") String FromNumber, @RequestParam("To") String ToNumber) throws PlivoXmlException { Map AgentCustomerMap = HashBiMap.create(CustomerAgentMap).inverse(); Response response = new Response(); if(CustomerAgentMap.containsKey(FromNumber)) { // Check whether the customer's number is in the customer-agent mapping var DestNumber = CustomerAgentMap.get(FromNumber); // Assign the value from the customer-agent map to DestNumber variable response.children(new Dial() .callerId(ToNumber) // Plivo number is used as the caller ID for the call toward the agent .children(new Number(DestNumber))); } else if (AgentCustomerMap.containsKey(FromNumber)) { // Check whether the agent's number is in the customer-agent mapping var DestNumber = AgentCustomerMap.get(FromNumber); // Assign the Kky from the customer-agent map to DestNumber variable response.children(new Dial() .callerId(ToNumber) // Plivo number is used as the caller ID for the call toward the customer .children(new Number(DestNumber))); } System.out.println(response.toXmlString()); return response; } } ``` Save the file and run it. You should see your basic server application in action at [http://localhost:8080/number\_masking/](http://localhost:8080/number_masking/). [Set up ngrok](/sdk/server/set-up-java-dev-environment-api-xml-voice/#ngrok-setup) to expose your local server to the internet. Now people can call your Plivo number. If an incoming call to your Plivo number is from one of the customer phone numbers in the customer-agent map — for example, if the caller number is `14156667777` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. If the incoming call to your Plivo number is from one of the agent phone numbers in the customer-agent map — for example, if the caller number is `14156667778` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. ## Create a Plivo application Associate the Spring application you created with Plivo by creating a Plivo application. Visit Voice > [Applications](https://cx.plivo.com/xml-applications) in the Plivo console and click on **Add New Application**, or use Plivo’s [Application API](/account/api/application/#create-an-application). Give your application a name — we called ours `Number Masking`. Enter the server URL you want to use (for example, https\://\.ngrok.io/handleincoming/) in the `Answer URL` field and set the method as `GET`. Click **Create Application** to save your application. ## Assign a Plivo number to your application Navigate to the [Numbers](https://cx.plivo.com/phone-numbers) page and select the phone number you want to use for this application. From the Application Type drop-down, select `XML Application`. From the Plivo Application drop-down, select `Number Masking` (the name we gave the application). Click **Update Number** to save. ## Test To test the application, you need two Plivo numbers. Set up one of your numbers as a customer and another as an agent in the customer-to-agent mapping data in the config file. Make a call from each of your mobile numbers to the Plivo number you mapped to the application. You should see that the call is forwarded to the other number, and that the incoming call has the Plivo number as the caller ID. ## Overview Phone number masking hides the phone numbers of parties in a call from each other. Many businesses find it advantageous to anonymize communication between two parties — for example, between a customer and a delivery agent on a food delivery service platform or a driver and a rider using a ride-hailing application. Businesses can implement phone number masking by sending calls through an intermediate phone number that acts as a proxy between the two parties. A Plivo number can serve as the intermediate number to connect the two parties while keeping their contact information private. ## How it works As an example, we’ll build a number-masking application for a food delivery service that lets the company connect customers with delivery agents and vice versa without revealing any actual phone numbers. To do this, you 1. Create a customer-to-agent phone number mapping in your application’s back end. 2. Create the number masking application using Plivo. 3. Assign the number masking application to a Plivo number. ## Prerequisites To get started, you need a Plivo account — [sign up](https://cx.plivo.com/signup) with your work email address if you don’t have one already. You must have a voice-enabled Plivo phone number to receive incoming calls; you can rent numbers from the [Numbers](https://cx.plivo.com/phone-numbers) page of the Plivo console, or by using the [Numbers API](/numbers/). If this is your first time using Plivo APIs, follow our instructions to [set up a Go development environment](/sdk/server/set-up-go-dev-environment-api-xml-voice/) and a web server and safely expose that server to the internet. ## Create a 1:1 map with actual numbers Create customer-to-agent phone number mapping for the application. Whenever a customer places an order, their phone number should be stored in a database for your application to access. A delivery agent will be assigned for the order, and the agent’s number will also be stored in your database, and will be mapped to the customer's number: ``` Customer’s Number <-> Agent’s Number 1-415-666-7777 1-415-666-7778 ``` We created sample mapping data in a .env file: ```sh theme={null} json BASEMAP = {"14156667777":"14156667778","14156667779":"14156667780","14156667781":"14156667782"} ``` ## Create a Go server for number masking Create a file called `masking.go` and paste into it this code. ```go theme={null} package main import ( "encoding/json" "log" "os" "github.com/gin-gonic/gin" "github.com/joho/godotenv" "github.com/plivo/plivo-go/v7/xml" ) // init gets called before the main function func init() { // Log error if .env file does not exist err := godotenv.Load(".env") if err != nil { log.Fatal("Error loading .env file") } } // Handle incoming calls to a Plivo number, connect agent with customer and vice versa without revealing their actual phone numbers. func main() { r := gin.Default() r.GET("/number_masking", func(c *gin.Context) { customerAgentmap := os.Getenv("BASEMAP") // Declares an empty map interface var result map[string]string fromNumber := c.Query("From") toNumber := c.Query("To") // Unmarshal or Decode the JSON to the interface. json.Unmarshal([]byte(customerAgentmap), &result) agentCustomermap := reverseMap(result) _, custToagent := result[fromNumber] _, agenTocust := agentCustomermap[fromNumber] if custToagent { // Check whether the customer's number is in the customer-agent mapping destNumber := result[fromNumber] // Assign the value from the customer-agent array to number variable c.XML(200, xml.ResponseElement{ Contents: []interface{}{ new(xml.DialElement). SetCallerID(toNumber). // Plivo number is used as the caller ID for the call toward the agent SetContents([]interface{}{ new(xml.NumberElement). SetContents(destNumber), }), }, }) } else if agenTocust { // Check whether the agent's number is in the customer-agent mapping destNumber := agentCustomermap[fromNumber] // Assign the key from the customer-agent array to number variable c.XML(200, xml.ResponseElement{ Contents: []interface{}{ new(xml.DialElement). SetCallerID(toNumber). // Plivo number is used as the caller ID for the call toward the customer SetContents([]interface{}{ new(xml.NumberElement). SetContents(destNumber), }), }, }) } c.Header("Content-Type", "application/xml") }) r.Run() // listen and serve on 0.0.0.0:8080 (for Windows "localhost:8080") } // Reverse the Basemap from env file to get customer-agent mapping data func reverseMap(m map[string]string) map[string]string { n := make(map[string]string) for k, v := range m { n[v] = k } return n } ``` Save the file and run it. ```shell theme={null} $ go run masking.go ``` You should see your basic server application in action on [http://localhost:8080/number\_masking/](http://localhost:8080/number_masking/). [Set up ngrok](/sdk/server/set-up-go-dev-environment-api-xml-voice/#ngrok-setup) to expose your local server to the internet. Now people can call your Plivo number. If an incoming call to your Plivo number is from one of the customer phone numbers in the customer-agent map — for example, if the caller number is `14156667777` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. If the incoming call to your Plivo number is from one of the agent phone numbers in the customer-agent map — for example, if the caller number is `14156667778` — then Plivo will send the XML response to process the incoming call as below, and you can check the XML document in your browser. ## Create a Plivo application Associate the Go application you created with Plivo by creating a Plivo application. Visit Voice > [Applications](https://cx.plivo.com/xml-applications) in the Plivo console and click on **Add New Application**, or use Plivo’s [Application API](/account/api/application/#create-an-application). Give your application a name — we called ours `Number Masking`. Enter the server URL you want to use (for example, https\://\.ngrok.io/handleincoming/) in the `Answer URL` field and set the method as `GET`. Click **Create Application** to save your application. ## Assign a Plivo number to your application Navigate to the [Numbers](https://cx.plivo.com/phone-numbers) page and select the phone number you want to use for this application. From the Application Type drop-down, select `XML Application`. From the Plivo Application drop-down, select `Number Masking` (the name we gave the application). Click **Update Number** to save. ## Test To test the application, you need two Plivo numbers. Set up one of your numbers as a customer and another as an agent in the customer-to-agent mapping data in the config file. Make a call from each of your mobile numbers to the Plivo number you mapped to the application. You should see that the call is forwarded to the other number, and that the incoming call has the Plivo number as the caller ID.