Outbound Calling

An outbound call is a phone call that is dialed and goes “out” from a phone number, & in our case, our AI assistant will be doing the dialing.

There are 3 steps we will cover to send our first outbound phone call:

Create an Assistant: we will create an assistant & instruct it on how to conduct itself during the call
Get a Phone Number: we can either import existing numbers we own, or purchase one through Vapi
Call Your Number: we will set our assistant as the dialer, set the destination phone number, then make the call

We can then send the outbound call, hopefully someone picks up!

It is a violation of FCC law to dial phone numbers without consent in an automated manner. See Telemarketing Sales Rule to learn more.

Vapi’s Pizzeria

We will be implementing a simple order-taking assistant for a pizza shop called “Vapi’s Pizzeria”.

Vapi’s has 3 types of menu items: pizza, sides, & drinks. Customers will be ordering 1 of each.

Outbound Scenario: We will imagine we are calling back a customer who originally called in to place an order. Our assistant is calling back to complete the ordering process with the customer.

Customers can order 3 items: 1 pizza, 1 side, & 1 drink. The assistant will call the customer (who got disconnected) & finish the ordering process.

Assistant Setup

First we’re going to set up our assistant in the dashboard. Once our assistant’s transcriber, model, & voice are set up, we can have it call the customer to finish the order.

You can visit your dashboard by going to dashboard.vapi.ai

Now we’re going to set the “brains” of the assistant, the large language model. We’re going to be using GPT-4 (from OpenAI) for this demo (though you’re free to use GPT-3.5, or any one of your favorite LLMs).

Assistants can optionally be configured with a First Message. This first message will be spoken by your assistant when either:

A Web Call Connects: when a web call is started with your assistant
An Inbound Call is Picked-up: an inbound call is picked-up & answered by your assistant
An Outbound Call is Dialed & Picked-up: an outbound call is dialed by your assistant & a person picks up

Note that this first message cannot be interrupted & is guaranteed to be spoken. Certain use cases need a first message, while others do not.

For our use case, we will want a first message. Since we are calling the customer back it would be ideal for us to have a first message like this:

Hi this is Jennifer from Vappy’s Pizzeria giving you a call back since we got disconnected. Would you like to finish your order with us?

Some text-to-speech voices may struggle to pronounce ‘Vapi’ correctly, compartmentalizing it to be spoken letter by letter “V. A. P. I.”

Some aspects of configuring your voice pipeline will require tweaks like this to get the target behaviour you want.

This will be spoken by the assistant when a web or inbound phone call is received.

We will now set the System Prompt for our assistant. If you’re familiar with OpenAI’s API, this is the first prompt in the message list that we feed our LLM (learn more about prompt engineering on the OpenAI docs).

The system prompt can be used to configure the context, role, personality, instructions and so on for the assistant.

Since we are calling the customer back, we will tweak the base prompt a bit so the model understands the situation & new goal (recovering the order).

A system prompt like this will give us the behaviour we want:

You are a voice assistant for Vappy’s Pizzeria,
a pizza shop located on the Internet.

Your job is to take the order of customers calling in. The menu has only 3 types
of items: pizza, sides, and drinks. There are no other types of items on the menu.

1) There are 3 kinds of pizza: cheese pizza, pepperoni pizza, and vegetarian pizza
(often called "veggie" pizza).
2) There are 3 kinds of sides: french fries, garlic bread, and chicken wings.
3) There are 2 kinds of drinks: soda, and water. (if a customer asks for a
brand name like "coca cola", just let them know that we only offer "soda")

Customers can only order 1 of each item. If a customer tries to order more
than 1 item within each category, politely inform them that only 1 item per
category may be ordered.

Customers must order 1 item from at least 1 category to have a complete order.
They can order just a pizza, or just a side, or just a drink.

Be sure to introduce the menu items, don't assume that the caller knows what
is on the menu (most appropriate at the start of the conversation).

If the customer goes off-topic or off-track and talks about anything but the
process of ordering, politely steer the conversation back to collecting their order.

Once you have all the information you need pertaining to their order, you can
end the conversation. You can say something like "Awesome, we'll have that ready
for you in 10-20 minutes." to naturally let the customer know the order has been
fully communicated.

It is important that you collect the order in an efficient manner (succinct replies
& direct questions). You only have 1 task here, and it is to collect the customers
order, then end the conversation.

- Be sure to be kind of funny and witty!
- Keep all your responses short and simple. Use casual language, phrases like "Umm...", "Well...", and "I mean" are preferred.
- This is a voice conversation, so keep your responses short, like in a real conversation. Don't ramble for too long.

You are calling back a customer after the call got disconnected while they were
ordering. Your job is to help them complete their order.

You can copy & paste the above prompt into the System Prompt field. Now the model configuration for your assistant should look something like this:

Note how our model provider is set to OpenAI & the model is set to GPT-4.

Get a Phone Number

Now that we’ve configured how our assistant will behave, we want to figure out how to dial calls with it. We will need a phone number that we can call from.

There are 2 ways we can get a phone number into our Vapi account:

Purchase a Number Through Vapi: we can directly purchase phone numbers through Vapi.
- Vapi will provision the phone number for us via Twilio
- This can be done in the dashboard, or via the API (we will use the dashboard)
Import from Twilio or Vonage: if we already have a phone number with an external telephony provider (like Twilio or Vonage), we can import them into our Vapi account.

Call Your Number

We can now make outbound calls to phone numbers, setting our assistant as the one doing the dialing.

In the phone numbers section of the dashboard, go to your phone number detail page. We will:

fill out our own phone number as the number to dial
set our assistant as the one doing the calling

When we hit the call button, our assistant will make the outbound call to the phone number.

You can now hit the call button to make the outbound call. Your assistant will dial the phone number & manage the order recovery process.

Your assistant won’t yet be able to hang-up the phone at the end of the call. We will learn more about configuring call end behaviour in later guides.

General

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Core Concepts

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Glossary

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Outbound Calling

Vapi’s Pizzeria

Assistant Setup

Get a Phone Number

Call Your Number

General

Get Started

Core Concepts

Learn

Glossary

Community

Legal

​Vapi’s Pizzeria

​Assistant Setup

​Get a Phone Number

​Call Your Number

Vapi’s Pizzeria

Assistant Setup

Get a Phone Number

Call Your Number