> This page is part of the [Customer.io documentation](https://docs.customer.io). For the complete index, see [llms.txt](https://docs.customer.io/llms.txt).
> Last updated: July 10, 2026

# Reminders for multiple upcoming trips

## Introduction

This recipe is useful for multiple upcoming trips but you can also adapt it for these use cases:

*   Encourage a shopper to purchase their abandoned cart even when it’s possible for the user to have multiple carts.
*   Let a customer know that one of their many saved coupons is expiring soon.
*   Notify users when one job of many they’ve applied for is closed.

The idea is that sometimes people can have multiples of one thing - trips, carts, coupons, and job applications - and you may want to target a specific trip, cart, etc during a campaign. This recipe helps you do that!

We’ll create a campaign that reminds people to book a hotel for their upcoming trip. Since a customer can have multiple upcoming trips, we’ll make sure the reminder is about the correct trip and sent at the correct time.

## Ingredients

*   Basic knowledge of liquid
*   Ability to send events to Customer.io

## Method

This recipe will create two campaigns, one triggered by a `trip_booked` event and another by a `hotel_booked` event. You’ll store an attribute on people’s profiles, `trips_with_hotel_booked`, to track which trips already have a hotel booked. This way, you can ensure you only send the reminder to book a hotel for any trips *not* in that list.

### Campaign 1: Hotel is booked

Since we want to send a reminder if a hotel has not been booked, we need to track which trips include hotels. This campaign will do nothing more than add the trip’s `trip_id` to a comma separated list of ids in an attribute on the person’s profile indicating that they’ve booked the hotel— `trips_with_hotel_booked`. This is the attribute that is checked prior to sending the reminder in the campaign we’ll build next.

#### Send the event

You’ll want to send an event into [Customer.io](http://customer.io) for the user when they complete booking a hotel. In this example, we’re calling it `hotel_booked`. The event can contain any information about the hotel that you wish to include for use in other messages (maybe a confirmation email) that are triggered by the same event instance, but for the purposes of this capability, the only necessary attribute is the `trip_id`.

```
{
    "trip_id": "123"
}
```

For more details on sending events into Customer.io see our [API documentation](/integrations/api/track/#operation/track).

#### Create the campaign

Now that the event is sending to Customer.io, you can use it to trigger a campaign.

1.  Go to **Campaigns**.
2.  Click **Create Campaign**.
3.  Click **Choose trigger**.
4.  Select **Event** and choose `hotel_booked`.

[![multiple_reminders__hotel-booked-event](https://docs.customer.io/images/multiple_reminders__hotel-booked-event-1.png)](#dffa8bf35588639dfbffed065a2fb959-lightbox)

#### The workflow

The only item necessary in this workflow is an attribute update to add the `trip_id` to the comma separated list of ids named, `trips_with_hotel_booked`.

Drag a [**Create or update person** action](/messaging/send/workflows/attribute-updates/create-update-person) into your workflow. Click it then choose **Add details**.

[![multiple_reminders__attribute-update-hotel-booked](https://docs.customer.io/images/multiple_reminders__attribute-update-hotel-booked-1.png)](#3ab8a283c3c27147f8184b8784599891-lightbox)

The liquid for this update:

```
{% if customer.trips_with_hotel_booked != blank %}
  {{customer.trips_with_hotel_booked}},{{event.trip_id}}
{% else %}
  {{event.trip_id}}
{% endif %}
```

If the attribute doesn’t exist on the profile already, the *Create or update person* action will add it.

This is the only workflow item required to make this use-case work, but adding a confirmation email to this workflow would be an excellent way to manage the entire hotel booking process in one campaign.

[![multiple_reminders__campaign1-workflow](https://docs.customer.io/images/multiple_reminders__campaign1-workflow.png)](#1ac3efd69e7a87c79001c393b23e4935-lightbox)

### Campaign 2: Trip is initially booked

You’ll create a campaign triggered by the initial booking event. This will be the campaign that sends the reminder message a specified amount of time after the initial booking.

#### Send the event

Just like the first campaign, you’ll want to send an event into [Customer.io](http://customer.io) for the user when they complete booking their trip. In this example, we’re calling it `trip_booked`. This event should contain any information about the trip that you care to include in the email reminding them to book their hotel. We’ve included destination, confirmation number, and trip\_date. It also needs to include a unique identifier for the event. We’ve used `trip_id` in this example:

```
{
    "trip_id": "123",
    "destination": "Melbourne, Australia",
    "confirmation": "N35RTX",
    "trip_date": "28-OCT-2020"
}
```

For more details on sending events into Customer.io see our [API documentation](/integrations/api/track/#operation/track).

#### Create the campaign

Now that the event is sending to Customer.io, you can use it to trigger a campaign.

1.  Go to **Campaigns**.
2.  Click **Create Campaign**.
3.  Click **Choose trigger**.
4.  Select **Event**.

[![multiple_reminders__trip-booked-event](https://docs.customer.io/images/multiple_reminders__trip-booked-event-1.png)](#38683fde2f654186963894b43214921e-lightbox)

#### The workflow

The first item your workflow needs to contain is a delay set to the amount of time you’d like to wait before sending the reminder. In this case, we’ll remind them after 10 days.

[![multiple_reminders__delay](https://docs.customer.io/images/multiple_reminders__delay.png)](#9f839a89b74be1bd49efb7e1e9d5e62b-lightbox)

Once someone waits 10 days and exits the delay, we want to check whether they’ve booked the hotel for this trip yet. If not, we’ll send them a reminder to do so. To create this logic, add a **True/False Branch** to the workflow. In this case, you want to check whether the `trips_with_hotel_booked` **attribute for this person** contains the `trip_id` for **this event**. To do this, use the ‘attribute condition’ in the True/False Branch.

[![multiple_reminders__add-attribute-condition](https://docs.customer.io/images/multiple_reminders__add-attribute-condition-1.png)](#dc9aad2aab9215d8dfccba104d04b6e3-lightbox)

Enter the attribute `trips_with_hotel_booked` and then select the option to compare it to an event attribute. And finally, enter `trip_id` as the event attribute to check.

[![multiple_reminders__event-attribute](https://docs.customer.io/images/multiple_reminders__event-attribute-1.png)](#b1832e1fb7b8443b10b2327204379533-lightbox)

If the hotel has been booked for this trip, we don’t need to send them a reminder, but we do want to clear the `trip_id` from the `trips_with_hotel_booked` to clean things up and make sure the attribute doesn’t hit [length limits](/integrations/api/track/#section/Track-API-limits). To do this, add a **Create or update person** action to the True branch.

[![multiple_reminders__campaign2-workflow](https://docs.customer.io/images/multiple_reminders__campaign2-workflow.png)](#d58d51d63ca7cb289b327195db6de3d8-lightbox)

This should update the `trips_with_hotel_booked` attribute by removing it from the list. Here’s the liquid for this update:

```fallback
{% assign trips = trips_with_hotel_booked | split: "," %}
{% assign updated_trips = "" %}
{% for trip in trips %}
  {% if trip != "" and trip != event.trip_id %}
    {% if updated_trips != blank %}
      {% assign updated_trips = updated_trips | append: "," %}
    {% endif %}
    {% assign updated_trips = updated_trips | append: trip %}
  {% endif %}
{% endfor %}
{{updated_trips}}
```

#### The reminder email

Now the fun part! With the data in the original `trip_booked` event, you can craft a personalized email reminding and encouraging them to book their hotel for the trip.

[![multiple_reminders__email](https://docs.customer.io/images/multiple_reminders__email-1.png)](#c1b3c7c950e9888ac838e62727081ed5-lightbox)

#### The final workflow

To recap, this campaign will hold the person in a delay for 10 days after booking the trip. After 10 days have passed, it will check whether they’ve booked a hotel for the trip. If so, it will simply clean up the attribute tracking that hotel booking, but if not, it will send a reminder to book a hotel for that particular trip. The workflow should look something like this:

[![multiple_reminders__campaign2-final-workflow](https://docs.customer.io/images/multiple_reminders__campaign2-final-workflow.png)](#701e38c5bfa84d4411cd407a0eb89b9f-lightbox)

## Wrap Up

Using profile attributes to store status of multiple active trips on the customer account is a great way to customize your messaging for each of those trips. If this approach doesn’t work for you, though, or you need help getting it set up, send us a message!

*   *   [Introduction](#introduction)
    *   [Ingredients](#ingredients)
    *   [Method](#method)
        *   [Campaign 1: Hotel is booked](#campaign-1-hotel-is-booked)
            *   [Send the event](#send-the-event)
            *   [Create the campaign](#create-the-campaign)
            *   [The workflow](#the-workflow)
        *   [Campaign 2: Trip is initially booked](#campaign-2-trip-is-initially-booked)
            *   [Send the event](#send-the-event-1)
            *   [Create the campaign](#create-the-campaign-1)
            *   [The workflow](#the-workflow-1)
            *   [The reminder email](#the-reminder-email)
            *   [The final workflow](#the-final-workflow)
    *   [Wrap Up](#wrap-up)

Copy page

Copy page [Download .md](/messaging/send/recipes/reminders-for-multiple-upcoming-trips.md)

Is this page helpful?

![](https://docs.customer.io/images/export-success.png) ![](https://docs.customer.io/images/export-failure.png)

# How can we make it better?

Close

Do you need help from Customer.io support?  No  
 Yes

What part of Customer.io do you need help with? 

How can we improve this page?

Email (optional):  Please provide a valid email address

 I am not a bot

 

We appreciate your feedback!

Our support team will contact you as soon as possible