python-backend-demo

This is a sample demo repo to show how to have your own LLM plugged into Retell.

This repo currently uses OpenAI endpoint, and is not as stable and fast as Azure OpenAI endpoint. So expect a more varying delay. Feel free to contribute to make this demo more realistic.

Steps to run in localhost

1. First install dependencies

pip3 install -r requirements.txt

2. Fill out the API keys in .env

3. In another bash, use ngrok to expose this port to public network

ngrok http 8080

4. Start the websocket server

uvicorn server:app --reload --port=8080

You should see a fowarding address like https://dc14-2601-645-c57f-8670-9986-5662-2c9a-adbd.ngrok-free.app, and you are going to take the IP address, prepend it with wss, postpend with llm-websocket path and use that in the dashboard to create a new agent. Now the agent you created should connect with your localhost.

The custom LLM URL would look like wss://dc14-2601-645-c57f-8670-9986-5662-2c9a-adbd.ngrok-free.app/llm-websocket

Optional: Phone Call Features via Twilio

The twilio_server.py contains helper functions you could utilize to create phone numbers, tie agent to a number, make a phone call with an agent, etc. Here we assume you already created agent from last step, and have agent id ready.

To ues these features, follow these steps:

1. Uncomment twilio client initialization and listen_twilio_voice_webhook(agent_id_path) in server.py file to set up Twilio voice webhook. What this does is that every time a number of yours in Twilio get called, it would call this webhook which internally calls the register-call API and sends the correct audio websocket address back to Twilio, so it can connects with Retell to start the call.

2. Put your ngrok ip address into .env, it would be something like https://dc14-2601-645-c57f-8670-9986-5662-2c9a-adbd.ngrok-free.app.

3. (optional) Call create_phone_number to get a new number and associate with an agent id. This phone number now can handle inbound calls as long as this server is running.

4. (optional) Call register_phone_agent to register your Twilio number and associate with an agent id. This phone number now can handle inbound calls as long as this server is running.

5. (optional) Call delete_phone_number to release a number from your Twilio pool.

6. (optional) Call transfer_call to transfer this on-going call to a destination number.

7. (optional) Call end_call to end this on-going call.

8. Call create_phone_call to start a call with caller & callee number, and your agent Id. This call would use the agent id supplied, and ignore the agent id you set up in step 3 or 4. It automatically hang up if machine/voicemail/IVR is detected. To turn it off, remove "machineDetection, asyncAmd" params.

Run in prod

To run in prod, you probably want to customize your LLM solution, host the code in a cloud, and use that IP to create agent.