Use case: Booking reminder email system

Braze is a comprehensive customer engagement platform that is designed to be highly programmatically controllable. In this use case, we’ll demonstrate just a few ways in which Braze provides functionality you can plug into use cases that sit at the intersection of product and marketing, such as booking systems.

This use case shows how you can use Braze features to build a booking reminder email messaging service. The service will allow users to book appointments and will message users with reminders of their upcoming appointments. Though this use case uses email messages, you can send messages in any, or multiple, channels based on a single update to a user profile.

Other benefits of creating this service include:

• Sent messages will have full tracking and reporting.
• Message content can be updated by non-technical Braze users.
• Messages obey opt-in and opt-out statuses on user profiles per campaign configuration.
• Both booking data and message interaction data can be used to segment and target users for additional messaging. For example, you can retarget those who don’t open the initial reminder message with an additional reminder before their appointment.

Follow these steps to achieve this use case:

1. Write upcoming booking data to a Braze user profile
2. Set up and launch a booking reminder message
3. Handle updated bookings and cancellations

Step 1: Write upcoming booking data to a Braze user profile

Use the Braze /users/track endpoint to write a nested custom attribute to a user profile each time a booking takes place. Make sure the nested custom attribute contains all the information that will be needed to send and personalize the reminder message. In this use case, we’ll name the nested custom attribute “trips”.

Add booking

When a user creates a booking, use the following structure for the array of objects to send the data to Braze through the /users/track endpoint.

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{
 "attributes": [
       {
           "external_id": "test-user",
           "_merge_objects": true,
           "trips": [
               {"trip_id":"1","name":"London Trip","start_date"{$time:"2025-11-11"}},
               {"trip_id":"2","name":"Sydney Trip","start_date"{$time:"2025-11-11"}}
           ]
       }
   ]
}

The nested custom attribute “trips” will display in the user profile like so.

Update booking

When a user updates a booking, use the following structure for the array of objects to send the data to Braze through the /users/track endpoint.

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{
 "attributes": [
       {
           "external_id": "test-user",
           "_merge_objects": true,
           "trips": {
               "$update:":[
                   {
                       "$identifier_key":"trip_id",
                       "$identifier_value":"1",
                       "$new_object":{"trip_id":"1","name":"London Trip","start_date":{"$time":"2025-11-11"}}
                   }
               ]
           }
       }
 ]
}

Remove booking

• /users/track endpoint
• sdk

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{
 "attributes": [
       {
           "external_id": "test-user",
           "_merge_objects": true,
           "trips": {
               "$remove:":[
                   {
                       "$identifier_key":"trip_id",
                       "$identifier_value": "1"
                   }
               ]
           }
       }
   ]
}

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const json = [{
  "id": 1,
  "name": "London Trip",
  "start_date": {"$time”: “2025-05-08”}
}, {
  "id": 1,
  "name": "Sydney Trip",
  "start_date": {"$time”: “2025-11-11”}
}];
braze.getUser().setCustomUserAttribute("trips", json);

The specified booking will be removed from the nested custom attribute in the user profile and display any remaining bookings.

Step 2: Set up and launch a booking reminder message

Step 2a: Create a target audience

Create a target audience to receive reminders using multi-criteria segmentation. For example, if you want to send a reminder two days before the booking date, select the following:

• A start date in more than 1 days and
• A start date in less than 2 days

Step 2b: Create your message

Create the reminder email message by following the steps in Creating an email with custom HTML. Use Liquid to personalize the message with data from the custom customer attribute you created (“trips”), such as in this example.

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{% assign dates = {{custom_attribute.${trips}}} %}
{% assign today = "now" | date: "%s" %}
{% assign two_days = today | plus: 172800 | date: "%F" %}
You have the following booked in 2 days! Check the information below:
{% for date in dates %}
{% if date.start_date == two_days %}
{{date.trip_id}} 
{{date.name}}
{% endif %}
{% endfor %}

Step 2c: Launch your campaign

Launch the campaign for the reminder email message. Now, each time Braze receives the “trips” custom attribute, a message will be scheduled according to the data included in the respective booking’s object.

Step 3: Handle updated booking updates and cancellations

Now that you’re sending reminder messages, you can set up confirmation messages to send when bookings are updated or canceled.

Step 3a: Send updated data

• /users/track
• sdk

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{
  "events": [
    {
      "external_id": "user_id",
      "name": "trip_updated",
      "time": "2025-03-07T08:19:23+01:00",
      "properties": {
        "id": 2,
        "name": "Sydney Trip",
        "old_time": "2025-11-12"
        "new_time": "2026-01-21"
      }
    }
  ]
}

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braze.logCustomEvent("trip_updated", { 
  id: 2,
  name: "Sydney Trip",
  old_time: "2025-11-12",
  new_time: "2026-01-21"
});

Step 3b: Create a message to confirm the update

Create an action-based campaign to send the user a confirmation of their updated booking. You can use Liquid to template event properties that reflect the name, old time, and new time of the booking (or just the name if it’s a cancellation) into the message itself.

For example, you could compose the following message:

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Hi {{${first_name}}}, you have successfully updated the date of your trip, {{event_properties.${name}}}, from {{event_properties.${old_time}}} to {{event_properties.${new_time}}}

Step 3c: Modify the user profile to reflect the update

Finally, to send the booking reminders from steps 1 and 2 based on the most recent data, update the nested custom attributes to reflect the change or cancellation in the booking.

Updated booking

If the user in this use case updated their Sydney trip, you’d use the /users/track endpoint to change the date with a call like this:

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{
  "attributes": [
    {
      "external_id": "user_id",
      "_merge_objects": true,
      "trips": {
	  "$update": [
	    {
            "$identifier_key": "id",
            "$identifier_value": 2,
            "$new_object": {
              "start_date": "2026-01-21"
            }
          }
        ]
      }
    }
  ]
}

Cancelled booking

If the user in this use case cancelled their Syndey trip, you’d send the following call to the /users/track endpoint:

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{
  "attributes": [
    {
      "external_id": "user_id",
      "trips": {
	  "$remove": [
	   {
            "$identifier_key": "id",
            "$identifier_value": 2
          }
         ]
      }
    }
  ]
}

After these calls are sent and the user profile is updated, the booking reminder messages will reflect the latest data about the user’s booking dates.