Build an AI powered customer service voice agent on AWS

A few weeks ago, I found myself in Vegas, trying to update a dinner reservation on a packed Saturday night. Calling the restaurant was useless—there was no chance of getting through. That got me thinking: how quickly could I spin up an AI-powered reservation assistant?

So, I put it to the test. In under an hour, I built a crude proof of concept (PoC) using AWS services. The setup was simple:

• Amazon Connect to handle incoming calls

• Amazon Lex for voice interaction and capturing reservation details

• AWS Lambda to process and store the reservation

• Amazon DynamoDB for storing reservations

• Amazon SES to send confirmation emails

This isn’t about cutting-edge AI. It’s about solving real problems—fast. AI isn’t useful unless it’s applied to the right problem, and once you do that, impact follows almost instantly.

Now, let’s dive into how I built it.

Architecture

Setting Up Amazon Connect for Call Routing

Create an Amazon Connect Instance

1. Go to the AWS Console → Amazon Connect → Create an instance.

2. Set up an administrator account and choose a name for the instance.

3. Follow the instance creation flow to claim a phone number and use it for incoming calls

Now, whenever someone calls this number, we can define what happens next using a contact flow.

Configure a Contact Flow to Invoke Lex

A contact flow is a set of actions Amazon Connect follows when handling a call. Under bot create a Lex bot. After configuring the bot, create an “intent” to capture user request to make reservations.

Additionally, the call flow I configured a welcome prompt and terminating the call after capturing the required information

Creating an Amazon Lex Bot for Reservations

Define the Lex Bot and Intent

Amazon Lex is AWS’s conversational AI service, handling both text and voice inputs.

1. In Amazon Lex, create a new bot called ReservationBot.

2. Under Intents, create a new intent called MakeReservation.

3. Add sample utterances like:

   • I want to make a reservation

   • Can I book a table for tonight?

   • Reserve a table for two at 7 PM

Add Slots to Capture User Data

Slots are variables that store user inputs. Add the following slots to MakeReservation:

Configure Fulfillment with AWS Lambda

Once Lex collects user input, we need to process the reservation and store it in DynamoDB.

1. In Lex, go to the Fulfillment section.

2. Select AWS Lambda function and create a new function.

3. Use the following Python code:

import boto3
import uuid

dynamodb = boto3.resource("dynamodb")
table = dynamodb.Table("Reservations")

def lambda_handler(event, context):
    slots = event["currentIntent"]["slots"]

    reservation_id = str(uuid.uuid4())
    reservation_data = {
        "ReservationID": reservation_id,
        "FirstName": slots["firstName"],
        "PhoneNumber": slots["phoneNumber"],
        "PartySize": slots["partySize"],
        "Date": slots["date"],
        "Time": slots["time"]
    }

    table.put_item(Item=reservation_data)

    return {
        "dialogAction": {
            "type": "Close",
            "fulfillmentState": "Fulfilled",
            "message": {
                "contentType": "PlainText",
                "content": f"Your reservation is confirmed, {slots['firstName']}! Your confirmation ID is {reservation_id}."
            }
        }
    }

This function:
✅ Extracts user inputs from Lex
✅ Generates a unique reservation ID
✅ Stores the reservation in DynamoDB
✅ Returns a confirmation message

Sending Confirmation Emails with Amazon SES

Once the reservation is stored, we want to send a confirmation email. Modify the Lambda function to include this:

def send_email(to_address, first_name, reservation_id):
    subject = "Your Reservation is Confirmed!"
    body = f"Hello {first_name},\n\nYour reservation is confirmed. Your confirmation ID is {reservation_id}.\n\nThank you!"

    response = ses.send_email(
        Source="your-email@example.com",
        Destination={"ToAddresses": [to_address]},
        Message={
            "Subject": {"Data": subject},
            "Body": {"Text": {"Data": body}}
        }
    )
    return response

Update the lambda_handler function to call send_email():

send_email(slots["phoneNumber"] + "@example.com", slots["firstName"], reservation_id)

Now, once a reservation is made, an email confirmation is sent to the customer.

Testing the Full Setup

Test the Call Flow in Amazon Connect

• Call the phone number assigned to Amazon Connect.

• Try making a reservation by voice.

• Ensure the data is stored in DynamoDB and a confirmation email is sent.

This setup isn’t complex, and that’s the beauty of it. In under an hour, we built a fully functional AI-powered reservation system using AWS services. The key takeaways:

✅ Amazon Connect + Lex makes voice call automation easy.
✅ Lambda + DynamoDB handles backend processing and storage.
✅ Amazon SES automates email confirmations.

This solution can be expanded in many ways—multi-language support, SMS confirmations via SNS, or even integrating with restaurant POS systems. But the core idea remains: AI is most effective when applied to the right problems.