Abandoned cart tutorial

Overview

Abandoned carts are one of the highest-impact opportunities to recover lost revenue. Most users who abandon a cart still intend to purchase — they just need a timely reminder. This guide shows you how to build an automated abandoned cart Journey in OneSignal that:

Detects cart activity
Waits for a short period of inactivity
Sends a personalized reminder
Stops messaging immediately after purchase or cart removal

You can implement this using either:

Custom Events (recommended for most implementations)
Tags (simpler, limited to track 1 item instead of multiple)

The right choice depends on the data you want to show in the message and where that data comes from. What you will build By the end of this guide, you will have:

Cart activity sent to OneSignal (via Tags or Custom Events)
A clear, code-defined abandonment signal
Message templates that personalize cart data
A Journey that:
- Starts when an abandonment signal is received
- Waits before sending
- Sends abandoned cart messages
- Exits immediately when the cart is emptied or purchased
- Re-enters the Journey if the user still has items in their cart within a specific time period
Analytics to measure message and revenue performance

How abandoned carts are modeled This guide assumes you are tracking “cart updated” actions, meaning each time a user adds or removes items from their cart. This could be a single item like a subscription to your content or multiple items like a shopping cart. Once OneSignal receives a cart_updated event or tag:

The user becomes eligible to enter the Journey
A wait period gives them time to return naturally
Messages are sent only if they do not exit
The user exits immediately when the cart is emptied

Setup

Step 1: Plan your cart data and source

Decide what cart information you want to show and where that data comes from. Common cart data includes:

Product name, image, price, and quantity
Number of items in the cart
A deep link back to the cart

Your data source determines how you send events:

Data source	Recommended method
App or website	OneSignal Frontend SDK
Backend or database	OneSignal REST API
Third-party platform	Integration-based Custom Events

By the end of this step, you know what data you will send and how you will send it.

Step 2: Send cart activity to OneSignal

When the cart state changes, send the updated cart data to OneSignal so the activity can be tracked. This guide uses the event or tag cart_updated to track cart activity and at least one property. Select the method you chose in Step 1:

Custom Events
Tags

Send a cart_updated Custom Event each time the cart changes. Include product properties when items are in the cart and omit them when the cart is emptied.

Reference	Description
`trackEvent` method	Send via Frontend SDK (Mobile SDK, Web SDK)
Custom Events API	Send via REST API
Integrations	Send via integration

Frontend SDK trackEvent method example

OneSignal.User.trackEvent("cart_updated", {
  product_name: "24 Pack of Acorns",
  product_image: "https://i.imgur.com/ssPCfbC.png",
  product_price: 12.99,
  product_quantity: 1,
  cart_url: "https://yourdomain.com/cart"
});

OneSignal.User.trackEvent("cart_updated");

Custom Events API example

{
  "events": [
    {
      "name": "cart_updated",
      "properties": {
        "product_name": "24 Pack of Acorns",
        "product_image": "https://i.imgur.com/ssPCfbC.png",
        "product_price": "$12.99",
        "product_quantity": "1",
        "cart_url": "https://yourdomain.com/username/cart"
      },
      "external_id": "ID_OF_THE_USER"
    }
  ]
}

{
  "events": [
    {
      "name": "cart_updated",
      "external_id": "ID_OF_THE_USER"
    }
  ]
}

Set tags when items are in the cart and remove them when the cart is emptied.

These examples set the cart_updated tag to a Unix timestamp (in seconds) representing when the cart was last updated. You can also use a boolean value (true/false), but a timestamp provides more flexibility with Time Operators.

Reference	Description
`addTags` / `removeTags`	Send via Frontend SDK (Mobile SDK, Web SDK)
Update User API	Send via REST API

Frontend SDK addTags / removeTags methods example

OneSignal.User.addTags({
  cart_updated: unix_timestamp_seconds,
  product_name: "24 Pack of Acorns", 
  product_image: "https://i.imgur.com/ssPCfbC.png",
  product_price: "$12.99",
  product_quantity: "1",
  cart_url: "https://yourdomain.com/username/cart"
})

OneSignal.User.removeTags([
  "cart_updated", "product_name", "product_image", "product_price", "product_quantity", "cart_url"
])

Update User API example

{
  "properties": {
    "tags": {
      "cart_updated": 1779305030, // Unix timestamp in seconds
      "product_name": "24 Pack of Acorns",
      "product_image": "https://i.imgur.com/ssPCfbC.png",
      "product_price": "$12.99",
      "product_quantity": "1",
      "cart_url": "https://yourdomain.com/username/cart"
    }
  }
}

{
  "properties": {
    "tags": {
      "cart_updated": "",
      "product_name": "",
      "product_image": "",
      "product_price": "",
      "product_quantity": "",
      "cart_url": ""
    }
  }
}

Cart activity is now being sent to OneSignal. Each time the cart changes, OneSignal receives the updated data needed to trigger and personalize messages.

Step 3: Create abandoned cart message templates

Create message templates that reference cart data dynamically. For more details on the concepts used in this section, see:

Custom Event Push Template
Tag Push Template

Reference event properties using liquid syntax format:

Liquid

{{journey.event.name.properties.property_name | default: "fallback_value"}}

Message:

Liquid

You left {{journey.event.cart_updated.properties.product_name | default: "items"}} in your cart.

Image:

Liquid

{{journey.event.cart_updated.properties.product_image | default: "https://i.imgur.com/ssPCfbC.png"}}

Launch URL:

Liquid

{{journey.event.cart_updated.properties.cart_url | default: "https://yourdomain.com/cart"}}

The image will not display if product_image is not a direct, publicly accessible image URL.If your product_image is the name of an image file available online, you can reference the image using the following format: https://yourdomain.com/images/{{journey.event.cart_updated.properties.product_image | default: "stock_image"}}.png

Abandoned cart template example with Custom Events

Reference tag properties using liquid syntax format:

Liquid

{{tag_key | default: "fallback_value"}}

Message:

Liquid

You left {{product_name | default: "items"}} in your cart.

Image:

Liquid

{{product_image | default: "https://i.imgur.com/ssPCfbC.png"}}

Launch URL:

Liquid

{{cart_url | default: "https://yourdomain.com/cart"}}

Abandoned cart template example with Tags

Need email examples, help, or more inspiration?

Personalize messages with Custom Events

Complete guide to using Custom Events in Journeys. Includes event storage, Journey configuration, abandoned cart example, best practices, and troubleshooting.

Personalize messages with Properties

Complete guide to using Properties and Tags in Journeys. Includes event storage, Journey configuration, abandoned cart example, best practices, and troubleshooting.

Step 4: Create abandoned cart Segment (Tags only)

This step is only required if you are using Tags to track cart activity. If you are using Custom Events, you can skip this step.

The Segment will determine who can enter the Journey. See Segments for more details. Add two filters to the Segment:

User Tag — cart_updated exists
Last Session — less than 7 days ago - Adjust the time period as desired

Abandoned Cart Segment with Tag Filter where the cart_updated tag exists and the last session is less than 7 days ago

You can now track users that update their cart and have visited the app or website in the last 7 days.Users are automatically removed from the segment when either of the following conditions are met:

After 7 days have passed since they last visited the app/website
When the cart_updated tag is removed

Step 5: Create the abandoned cart Journey

Create a Journey that reacts to cart activity. See Journeys for more details.

New Abandoned Cart Journey create screen

Journey settings

Review the Journey Settings guide for more details on Entry, Exit, and Re-entry rules. Entry Rules:

Custom Event: Entry Rules
Tag: Entry Rules

Select Custom Event
Custom Event Name: cart_updated
Filter by property: With all of the following properties: product_name exists

Using Custom Events allows individual users to enter Journeys multiple times.Use properties to filter users so they only enter when a specific property exists.

Abandoned Cart Journey Custom Event Entry Rules

Exit Rules:

Custom Event: Exit Rules
Tag: Exit Rules

Users should exit the Journey when they empty their cart or complete the Journey.

Select Meet a certain condition
Check Exit when custom event condition occurs
Custom Event Name: cart_updated

Abandoned Cart Journey Custom Event Exit Rules

This configuration uses the same Custom Event name (cart_updated) for both entry and exit rules.This allows the user to only be in the Journey once at a time. Each time they update their cart, that instance of the user will exit and a new instance of the same user will enter the Journey. This is why it is important to use properties to filter users within the Entry Rules.

Re-entry Rules (Tags only):

Select Yes, after a certain amount of time
Set the re-entry time to 3 Days - Adjust the time period as desired

If you have followed this guide completely so far, then users will:

Enter the Journey when they abandon/update their cart
Exit the Journey when they empty their cart or complete the Journey.
Be eligible to re-enter the Journey:
- Custom Events: Each time the cart_updated event is performed
- Tags: After 3 days have passed since they last exited the Journey and are in the segment.

Journey steps

Users will enter the Journey based on your Entry Rules. This typically happens within a few minutes after the event/tag is received. Users will flow through the Journey step-by-step until they reach the end or an Exit Rule is met. A basic abandoned cart Journey does two things:

Gives the user enough time to empty their cart (make a purchase or remove items manually)
If they do not, sends a message reminding them about the items in their cart

Achieve this by first adding a Wait step to the Journey.

Set the wait time to be as long as you want. We recommend setting it to 1 or 2 hours so you can message them while they still have the intent to purchase.

Add a Message step.

Select the Abandoned Cart Push Notification template you created in Step 3.

Basic Abandoned Cart Journey is now configured.When a user enters the Journey, they will wait for 1 hour. If they do not exit the Journey, they will receive the abandoned cart push notification.

Advanced Journey Setup

Extend the Journey to send more messages over time for higher recovery rates.

Message sequence

A common high-performing cadence is:

Send the first message after 1 hour (completed in this guide).
Add another Wait step for 1 day and send a second message (~24 hours since they updated their cart).
Add another Wait step for 2 days and send a third message (~72 hours since they updated their cart).

Message types and content

Depending on which channels you set up with OneSignal, you will achieve better results using an omnichannel approach.

This guide shows how to send a push notification message after the first hour. This is used as a helpful reminder to try capturing the sale while the user may still be online.
Consider using both a push and email for your 2nd message. Use this second message to highlight benefits and social proof with light urgency to encourage them to purchase.
For the final message of the sequence, use an email or maybe an SMS (depending on the use case) as a “last call”. Consider using a discount code or other incentive to encourage them to purchase.

Fallback messages

OneSignal’s Journeys provide Wait Until branching logic that you can use to check if a message was confirmed delivered, clicked or opened and if not performed within a certain time period, send a fallback message. This is extremely helpful for users who may have unsubscribed from a specific message channel. More details on how to setup fallback messages can be found in our Fallback Messages guide.

Track performance

Journey analytics can be used to track how the Journey as a whole is performing. You can also track each message performance using Template analytics.

Track revenue with Outcomes

To track revenue from this Journey, you can use Custom Outcomes. When a purchase is made, you can send the event as a “Custom Outcome” to track the revenue associated with the specific message sent. Custom Outcomes can be sent via the Mobile SDK or Web SDK.

Example: Send purchase outcome via frontend SDK

// Example: capture total price and item count at checkout
const checkoutPriceTotal = document.querySelector(".checkout-price-total").innerText;
const checkoutItemsTotal = document.querySelector(".checkout-items-total").innerText;

function updateOSOnCartPurchase(checkoutPriceTotal, checkoutItemsTotal) {
  const purchasePriceTotal = parseFloat(checkoutPriceTotal);
  const purchasedItemCount = parseInt(checkoutItemsTotal);

  OneSignalDeferred.push(function (OneSignal) {
    OneSignal.Session.sendOutcome("Purchase", purchasePriceTotal);
    OneSignal.Session.sendOutcome("Purchased Item Count", purchasedItemCount);
  });
}

const submitPurchaseButton = document.querySelector(".submit-payment");
if (submitPurchaseButton) {
  submitPurchaseButton.addEventListener("click", () => {
    updateOSOnCartPurchase(checkoutPriceTotal, checkoutItemsTotal);
  });
}

Outcomes can attribute revenue to messages users clicked or were influenced by within a defined attribution window.

You have successfully implemented an abandoned cart Journey. When you are ready to start sending messages, select Set Live.

FAQ

Should I use Custom Events or Tags for cart tracking?

Custom Events are recommended for most implementations. They support richer data, allow property-based filtering in Journey entry rules, and automatically handle re-entry when the same event fires again. Tags work for simpler use cases where you only need to track whether a cart exists, but require manual segment creation and re-entry configuration.

How long should I wait before sending the first reminder?

One to two hours is a common starting point. This gives the user enough time to return on their own while the purchase intent is still fresh. Test different wait times and use Journey analytics to find what works best for your audience.

What happens if a user updates their cart while in the Journey?

With Custom Events, the user exits the current Journey instance (because cart_updated fires as an exit condition) and immediately re-enters with the updated event data. With Tags, the user stays in the same Journey instance because the tag still exists — they only re-enter after exiting and waiting for the re-entry period.

Need help?Chat with our Support team or email support@onesignal.comPlease include:

Details of the issue you’re experiencing and steps to reproduce if available
Your OneSignal App ID
The External ID or Subscription ID if applicable
The URL to the message you tested in the OneSignal Dashboard if applicable
Any relevant logs or error messages

We’re happy to help!

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Abandoned cart tutorial

Overview

Setup

Step 1: Plan your cart data and source

Step 2: Send cart activity to OneSignal

Step 3: Create abandoned cart message templates

Personalize messages with Custom Events

Personalize messages with Properties

Step 4: Create abandoned cart Segment (Tags only)

Step 5: Create the abandoned cart Journey

Journey settings

Journey steps

Advanced Journey Setup

Message sequence

Message types and content

Fallback messages

Track performance

Track revenue with Outcomes

FAQ

Should I use Custom Events or Tags for cart tracking?

How long should I wait before sending the first reminder?

What happens if a user updates their cart while in the Journey?

​Overview

​Setup

​Step 1: Plan your cart data and source

​Step 2: Send cart activity to OneSignal

​Step 3: Create abandoned cart message templates

Personalize messages with Custom Events

Personalize messages with Properties

​Step 4: Create abandoned cart Segment (Tags only)

​Step 5: Create the abandoned cart Journey

​Journey settings

​Journey steps

​Advanced Journey Setup

​Message sequence

​Message types and content

​Fallback messages

​Track performance

​Track revenue with Outcomes

​FAQ

​Should I use Custom Events or Tags for cart tracking?

​How long should I wait before sending the first reminder?

​What happens if a user updates their cart while in the Journey?

Overview

Setup

Step 1: Plan your cart data and source

Step 2: Send cart activity to OneSignal

Step 3: Create abandoned cart message templates

Step 4: Create abandoned cart Segment (Tags only)

Step 5: Create the abandoned cart Journey

Journey settings

Journey steps

Advanced Journey Setup

Message sequence

Message types and content

Fallback messages

Track performance

Track revenue with Outcomes

FAQ

Should I use Custom Events or Tags for cart tracking?

How long should I wait before sending the first reminder?

What happens if a user updates their cart while in the Journey?