---title: Call & Text By Proxy (Masked Numbers) - Pythonslug: /guides/calltext-by-proxysidebar_position: 4x-custom: ported_from_readme: true---Overview--------This guide will show you how to create a bi-directional mask of participants phone numbers for voice and text messages using SignalWire and Python. What do you need to run this code?----------------------------------View the full code on our Github [here](https://github.com/signalwire/snippets-call-text-by-proxy)!You will need the [Python SignalWire SDK](pathname:///compatibility-api/rest/overview/client-libraries-and-sdks#python).How to Run Application----------------------### Build and Run on Docker1. Use our pre-built image from Docker Hub docker pull signalwire/snippets-call-text-proxy:python(or build your own image)1. Build your imagedocker build -t snippets-call-text-proxy .2. Run your imagedocker run --publish 5000:5000 --env-file .env snippets-call-text-proxy3. The application will run on port 5000### Build and Run NativelyTo run the application, execute export FLASK_APP=app.py then run flask run.You may need to use an SSH tunnel for testing this code if running on your local machine. – we recommend [ngrok](https://ngrok.com/). You can learn more about how to use ngrok [here](/guides/how-to-test-webhooks-with-ngrok). Step by Step Code Walkthrough-----------------------------### Setup Your Environment File1. Copy from example.env and fill in your values2. Save new file called .envYour file should look something like this.## This is the full name of your SignalWire Space. e.g., example.signalwire.comSIGNALWIRE_SPACE=# Your Project ID - you can find it on the API page in your Dashboard.SIGNALWIRE_PROJECT=# Your API token - you can generate one on the API page in your DashboardSIGNALWIRE_TOKEN=# The first proxy phone number youll be using for this guide. Must include the +1 SIGNALWIRE_NUMBER_1=+1xxxxxxxxxx# The second proxy phone number youll be using for this guide. Must include the +1 SIGNALWIRE_NUMBER_2=+1xxxxxxxxxx### Modify Your Proxy Session FileYou will need to edit proxy_sessions.json to reflect the correct participant numbers and the SignalWire numbers you choose to wish as proxy numbers. javascript[ { Session_Id: Demo123, Participant_A_Number: +15551237654, Participant_B_Number: +15553883000, Proxy_Number: +15556611212 }, { Session_Id: Demo234, Participant_A_Number: +15555181212, Participant_B_Number: +12347896543, Proxy_Number: +15556611212 }]### Configuring the CodeWhen the /lookup-session route is called, it will look up an active proxy session and create a back-to-back phone call that is proxied, or a proxied text message. **LEG A \<-> SIGNALWIRE PROXY \<-> LEG B** python# Lookup a proxy session by proxy number@app.route(/lookup-session, methods=[GET, POST])def lookup_session(): # Initialize SignalWire Client client = signalwire_client(os.environ[SIGNALWIRE_PROJECT], os.environ[SIGNALWIRE_TOKEN], signalwire_space_url = os.environ[SIGNALWIRE_SPACE]) # Read proxy number from request proxy_number = request.values.get(To) # Read participant number from request leg_1 = request.values.get(From) # read proxy sessions from json file with open(proxy_sessions.json) as f: sessions = json.load(f) # Lookup session, find session that has proxy number and participant that matches for session in sessions: # Lookup the second session participant, if A is calling if session[Proxy_Number] == proxy_number and session[Participant_A_Number] == leg_1: leg_2 = session[Participant_B_Number] found = True break # Lookup the second session participant, if B is calling elif session[Proxy_Number] == proxy_number and session[Participant_B_Number] == leg_1: leg_2 = session[Participant_A_Number] found = True break # We did not find anything yet found = False if found == True: # Check if a CallSid exists, if it does, it is a voice call if CallSid in request.values.keys(): # Bridge legs voice response = VoiceResponse() response.dial(leg_2, callerId = proxy_number) return str(response) # Check if a MessageSid exists, if it does it is a text message elif MessageSid in request.values.keys(): # Send a message, with challenge code to phone number provided. message = client.messages.create( from_ = proxy_number, body = request.values.get(Body), to = leg_2 ) return 200 else: # No session found response = VoiceResponse() response.say(We are sorry but your call can not be completed at this time. Good Bye!) return str(response)Wrap Up-------If you ever had a situation where you wanted to keep your phone number private between two parties, this example will help you out. Services like Lyft and Uber use technology like this every day to help protect the personal phone numbers of both passengers and drivers. There are many use cases for this, and we hope you find it helpful.Required Resources- [Github Repo](https://github.com/signalwire/snippets-call-text-by-proxy)- [Python SignalWire SDK](pathname:///compatibility-api/rest/overview/client-libraries-and-sdks#python) Sign Up Here------------If you would like to test this example out, you can create a SignalWire account and space [here](https://m.signalwire.com/signups/new?s=1).Please feel free to reach out to us on our [Community Slack](https://signalwire.community/) or create a Support ticket if you need guidance!
