Data feeds - OneSignal

Data Feeds let you pull real-time data from your APIs directly into messages at send time. This allows you to deliver highly personalized content without pre-loading data into OneSignal. Use Data Feeds when your data changes frequently, such as:

A user’s current rewards balance
Latest order status
Personalized product recommendations

Other personalization methods (like Tags or Dynamic Content) work well for static data. Data Feeds are best for live, fast-changing values.

Data Feeds are currently available only for email messages sent through Journeys. Need another channel? Fill out this short survey.

How Data Feeds work

Create a Data Feed – Configure how OneSignal connects to your API.
Attach the Data Feed to a message template.
Insert response fields in your message using Liquid syntax.
At send time, OneSignal makes an API call for each recipient, parses the response, and injects the data into your message.

Example: Display reward points

Suppose you want to show each customer their rewards balance:

Hi {{ first_name }},

You have {{ data_feed.rewards.points }} points!
Your membership status is {{ data_feed.rewards.status_level }}.

Keep shopping to earn more points!

When Sarah receives this email, the Liquid variables are replaced with her actual points balance and membership status. The following sections walk through setting up this example step by step.

Creating and using a Data Feed

1. Set up your Data Feed configuration

Navigate to Data > Data Feeds in the sidebar to see the list of existing Data Feeds and create a new one. Each Data Feed must have:

Name: A descriptive name like “Customer Rewards API” to help you distinguish feeds. Unique names are recommended but not required.
Alias: A short identifier like rewards used in Liquid syntax (e.g., {{ data_feed.rewards.points }}). Must be unique, lowercase, alphanumeric, with no spaces or special characters.
Method: The HTTP method OneSignal uses to contact your API. Usually GET, but POST is also supported.
URL: Your API endpoint. Supports Liquid syntax so OneSignal can fetch user-specific data.

For example, your rewards endpoint might accept the user’s external_id (stored in OneSignal) as a URL parameter:

https://acme.com/customers/user_id={{ external_id }}/rewards

Headers: Key-value pairs required by your API (e.g., authentication tokens). Supports Liquid syntax.
Body: Optional JSON request body. Supports Liquid syntax, the same as Journey webhooks.

For example, your API might require the user’s ID in the request body instead of the URL:

{
	"customer_id": "{{ subscription.external_id }}"
}

A complete Data Feed configuration looks like this:

Data Feed configuration showing name, alias, method, URL, and headers

Test your feed before using it in production. Data Feed tests run against your test subscriptions, so verify that those subscriptions have attributes that return a real result from your API.

Finally, Activate your new Data Feed so it’s ready for use.

2. Attach the Data Feed to your message template

Attach your Data Feed to your message template so that OneSignal knows to use it.

Navigate to Messages > Templates
In the Message section, select the Personalization button

Personalization button in the message template editor

Toggle on Data Feeds and select your feed

Data Feeds toggle and feed selector in the message composer

Save your template

3. Use the data in your message

Use Liquid syntax to insert response data anywhere in your message. Continuing the rewards example, the API response for Sarah (whose external_id is a1-b2c3) might look like this:

{
	"external_id": "a1-b2c3",
	"points": 193,
	"status_level": "Gold"
}

To insert the number of points and the status level, use dot notation to reference the Data Feed alias and response fields:

You have {{ data_feed.rewards.points }} points!
Your membership status is {{ data_feed.rewards.status_level }}.

This tells OneSignal:

Use a Data Feed
Use the rewards Data Feed
- Recall: the rewards feed knows to call the API with the external_id of the recipient
From the response, insert the value of the points item (193) and the status_level item (Gold)

Requirements and limits

Your API needs to:

Accept single-step authentication with auth tokens in headers
Respond quickly. Under 250ms recommended (this directly affects send speed)
Return JSON. Other formats are not supported at this time.
- If you need a different format, share your use case.
Handle your send volume. A low rate limit on your API slows message delivery.
Return reasonably-sized payloads. Keep responses under 50 KB for best performance.

Current limits:

One Data Feed per template. Fetch everything you need in a single API response.
One API call per Data Feed per message.
Journeys only. Not yet available for other sending methods.
No chaining calls. The payload from one Data Feed cannot be used to call another.

Need multiple Data Feeds per template or support for other channels? Share your use case to help prioritize these features.

Setting up your API

Before creating a Data Feed, ensure your API can handle these requirements:

Authentication

Your API should accept authentication via headers:

Authorization: Bearer YOUR_TOKEN

X-API-Key: YOUR_KEY

JSON request body

If you need to include a body in the request, your API should accept JSON. This may mean your headers need to include Content-Type: application/json.

JSON response

Your API should return a JSON object. Typically this means your headers will include Accept: application/json.

Personalization parameters

You’ll typically pass user identifiers in the URL like this:

https://api.example.com/users/{{external_id}}/data
https://api.example.com/rewards?email={{email | url_encode}}

And/or in the body:

{
	"customer_id": "{{ external_id }}",
	"email": "{{ subscription.email }}"
}

Make sure this data will exist in OneSignal (usually as Tags, but other options are available such as custom event properties).

Rate limits

Consider your API’s rate limits. Sending to 10,000 users means 10,000 API calls in rapid succession. Ensure your API can handle this volume.

Error handling

If your API returns an error or doesn’t have data for a user, the message won’t be sent to that recipient. Make sure your API returns data for all expected users.

Getting started checklist

Before implementing Data Feeds, answer these questions:

What data do I want to show in my message? Working backwards from a simple outline with the items to be populated from your API identified will help you organize your thinking.
Is this data available via a single API endpoint?
How will I authenticate API requests?
What identifier or other data item will I use to fetch personalized data?
Is that identifier already stored in OneSignal? If not, how will it be populated?
Can my API handle the volume of requests I’ll generate?
What happens if my API doesn’t have data for a user?

Examples and advanced use cases

Data Feeds can be used with Liquid syntax or in combination with other features in creative ways to produce more complex personalization.

Iterating with loops: abandoned cart
Custom events properties
Conditional display: order status
Automation without personalization
Personalized coupon codes

Let’s say you have a Data Feed cart that returns an array of items in the user’s cart, plus the cart total dollar amount:

{
  "items": [
    {
      "name": "Blue Running Shoes",
      "price": 84.00,
      "image_url": "https://acme.com/blue-running-shoes.png"
    },
    {
      "name": "Protein Bar",
      "price": 5.99,
      "image_url": "https://acme.com/protein-bar.png"
    }
  ],
  "total": 89.99
}

If you want to show each item in the cart, plus the cart total, you can use a for loop in Liquid:

<ul>
  {% for item in data_feed.cart.items %}
    <li>
      <strong>{{ item.name }}</strong><br>
      ${{ item.price }}<br>
      <img src="{{ item.image_url }}" alt="{{ item.name }}">
    </li>
  {% endfor %}
</ul>

<p>Cart total: ${{ data_feed.cart.total }}</p>

This will result in:

- Blue Running Shoes
- $84.00
- <running shoes image>
- Protein Bar
- $5.99
- <protein bar image>
Cart total: $89.99

If you’re using the email block editor, when inserting this sort of complex Liquid syntax, particularly if you need to include images or links, for best results use the custom HTML block element.

Want to see how to trigger this abandoned cart email using custom events? Check out the Custom events properties tab for the complete workflow.

Continuing the previous abandoned cart example, how might we know how to fetch that particular cart in the first place?One method might be to create a Journey triggered by a cart_abandoned custom event, where the properties includes a cart_id. In this example that event is being sent to OneSignal via API:

curl --request POST \
  --url https://api.onesignal.com/apps/{app_id}/custom_events \
  --header 'Accept: application/json' \
  --data '{
  "events": [
    {
      "name": "cart_abandoned",
      "external_id": "user_12345",
      "properties": {
        "cart_id": 98765
      }
    }
  ]
}'

Journey entry node triggered by a custom event

The user user_12345 enters the journey when this event is fired, then reaches a node sending an email. That email template is set up with the cart Data Feed, where the URL is set to retrieve the contents of a particular cart like so:

https://acme.com/carts/{{ journey.event.cart_abandoned.data.cart_id }}

Thus, when this particular event is ingested and triggers the Journey:

The cart_id value of 98765 will be stored to the Journey
When the email step is reached, the cart Data Feed will reference that cart_id value and use it to call the cart API
The returned JSON properties will be parsed and inserted into the email as in the previous example above

Want to see how to conditionally display Data Feed content based on order status? Check out the Conditional display: order status tab to learn more.

Let’s say you want to include the status of a customer’s order, but only include a tracking number link if the order has been shipped. You can use an if statement to do so:

Your order is {{data_feed.order.status}}!

{% if data_feed.order.tracking_number != empty %}
Track it here: {{data_feed.order.tracking_url}}
{% endif %}

Here, the tracking link will only be displayed if the tracking_number exists.

Data Feeds can be used to automatically insert up-to-date information into your messages without necessarily needing to be personalized per recipient.For example, perhaps you insert a banner image at the top of your emails and change it monthly to keep up with holidays and other monthly events. Rather than remembering to upload a new image to OneSignal and changing all your templates each month, you might set up a Data Feed that fetches the current banner image URL from your CMS or other asset-management location.You would set up a banner Data Feed that points to an endpoint without any variables in the URL like so:

https://acme.com/assets/email-banner

Which returns a response with the current banner URL:

{
	"banner_url": "https://acme.com/assets/email-banner/2025july.png"
}

You’d set your email template to use {{ data_feed.banner.banner_url }} as the image source URL, automating this process going forward.

This example covers how to send personalized, single-use coupon codes in emails using a Data Feed that fetches a unique value from your API for each recipient.

Goal

Send an email such as:

Hi George, Complete your booking in the next 2 hours and save 10% with your personal code: XYZ123ABC

Each user receives a unique coupon code, generated live via an external API call when the email is sent, valid for the given time window, and scoped to that user.

Prerequisites

Email channel configured in OneSignal (your app has email capability enabled)
An external API that accepts a user identifier (for example, external_id) and campaign identifier, and returns JSON with the coupon code, discount, and expiration
A unique identifier (such as external_id) for each user that your API can use to generate coupons
A segment or trigger (for example, “abandoned search in last 24h”) used to send the email through a OneSignal Journey

Step 1: Create the Data Feed

Navigate to Data Feeds

In your OneSignal app, select Data feeds from the navigation bar, then click New data feed.

Configure the Data Feed

Configure the following fields:

Data Feed Name: coupon_code_generator
Alias: coupon
Method: GET
URL: https://api.example.com/generate-coupon?userId={{ external_id }}&campaign=AbandonedBooking10

Headers:

{
  "Authorization": "Bearer YOUR_API_TOKEN"
}

Reference the API response

When the API returns JSON like this:

{
  "code": "AB10-5F3K-HT9L",
  "discount_percent": "10%",
  "expires_in_hours": 2
}

You can reference its values in your email template as:

{{ data_feed.coupon.code }}
{{ data_feed.coupon.discount_percent }}
{{ data_feed.coupon.expires_in_hours }}

Test and activate the Data Feed

Click Send Test to verify your configuration, then click Activate to make the Data Feed available for use in templates.

Step 2: Create the email template

In OneSignal, go to Messages → Email → New Template
Use the Data Feed alias and fields within your message body. For example:

<h2>Hi {{ first_name }},</h2>
<p>
Complete your booking in the next {{ data_feed.coupon.expires_in_hours }} hours and save
{{ data_feed.coupon.discount_percent }} with your personal code:
<strong>{{ data_feed.coupon.code }}</strong>
</p>

<p><a href="https://example.com/checkout?coupon={{ data_feed.coupon.code }}">Use Code Now →</a></p>

Use Liquid syntax in the form {{ data_feed.<alias>.<field> }}
Make sure the Data Feed is attached to the template
If using the drag-and-drop editor with custom Liquid logic, use an HTML block

Step 3: Attach the Data Feed and trigger the email

In the template composer, under Personalization, toggle Data Feeds and select your feed (coupon_code_generator)
This ensures OneSignal makes the API call at send time for each recipient, populates the data, and injects it into the email
Set up a Journey to automate the message:
- Entry condition: Segment such as “abandoned search in last 24 hours”
- Wait until: Create a booking_completed custom event. Configure the wait to exit the Journey if this event fires, or continue after 1 hour. If they complete a booking, they exit without receiving the email; otherwise, they continue to receive the coupon.
- Send email: Use the personalized coupon email template
- Ensure the Journey uses the email channel and that recipients are subscribed to email

Step 4: Manage coupon redemption and tracking

Your backend should:

Record each generated code along with userId, code, campaign, expiration_time, and a redeemed flag
Validate and mark codes as redeemed upon checkout
Log the redemption data (user, campaign, and time) for ROI analysis

Complete workflow example

Step	Event	Action
1	User triggers “abandoned search” segment	User enters Journey via segment
2	Journey triggers email send	OneSignal attaches Data Feed, calls your API with the user’s `external_id` and campaign name
3	API returns JSON	OneSignal populates data feed coupon fields and sends email
4	User receives email	Example: “Hi George! Save 10% with your personal code: AB10-5F3K-HT9L”
5	User redeems code	Backend validates and logs redemption

Testing

Test with a user who has a known external_id
Call your API manually to confirm correct JSON responses
Use Preview in the OneSignal template editor to verify that data feed coupon fields populate
Check API logs for latency and errors
If a Data Feed call fails, OneSignal will skip sending the message to that recipient

FAQ

My Data Feed values are not appearing in the message. What should I check?

Verify these in order:

The Data Feed is attached to the template (under Personalization > Data Feeds).
Your Liquid syntax matches the JSON response structure exactly — {{ data_feed.<alias>.<field> }}.
The API endpoint returns valid JSON when called manually with the same identifiers.
The recipient has the required identifier (e.g., external_id) stored in OneSignal.

Why are messages sending slowly?

Data Feed API calls run at send time for every recipient. If your API responds slowly or cannot handle concurrent requests, message delivery slows proportionally. Aim for under 250 ms response time and ensure your infrastructure can handle your send volume.

Why are some recipients not getting messages?

If the Data Feed API call fails for a recipient — due to a 404, timeout, or missing data — OneSignal skips that recipient entirely. Check the error log in your Data Feed configuration and your own API logs for failures. Verify those users have the required identifiers in OneSignal.

Can I use more than one Data Feed in a template?

Not currently. Each template supports one Data Feed. Fetch all the data you need in a single API response. If you need multiple feeds, share your use case.

Are Data Feeds available for push notifications or SMS?

No. Data Feeds are currently available only for email messages sent through Journeys. Support for additional channels is planned — share your use case to help prioritize.

What happens if my API is down when the message sends?

OneSignal skips any recipient whose Data Feed call fails. The message is not sent to that recipient, and no fallback value is inserted. Monitor your API uptime and error rates during scheduled sends.

Liquid syntax

Full reference for Liquid templating in OneSignal messages.

Journeys

Build automated messaging workflows that trigger Data Feed emails.

Custom events

Trigger Journeys and pass event properties for Data Feed URLs.

Message personalization

Overview of all personalization methods — tags, Liquid, dynamic content, and Data Feeds.

First steps & settings

Message channels

Journeys

Audience & custom events

Analytics & Integrations

Privacy & Security

​How Data Feeds work

​Example: Display reward points

​Creating and using a Data Feed

​1. Set up your Data Feed configuration

​2. Attach the Data Feed to your message template

​3. Use the data in your message

​Requirements and limits

​Setting up your API

​Authentication

​JSON request body

​JSON response

​Personalization parameters

​Rate limits

​Error handling

​Getting started checklist

​Examples and advanced use cases

​Goal

​Prerequisites

​Step 1: Create the Data Feed

​Step 2: Create the email template

​Step 3: Attach the Data Feed and trigger the email

​Step 4: Manage coupon redemption and tracking

​Complete workflow example

​Testing

​FAQ

​My Data Feed values are not appearing in the message. What should I check?

​Why are messages sending slowly?

​Why are some recipients not getting messages?

​Can I use more than one Data Feed in a template?

​Are Data Feeds available for push notifications or SMS?

​What happens if my API is down when the message sends?

​Related pages

Liquid syntax

Journeys

Custom events

Message personalization

How Data Feeds work

Example: Display reward points

Creating and using a Data Feed

1. Set up your Data Feed configuration

2. Attach the Data Feed to your message template

3. Use the data in your message

Requirements and limits

Setting up your API

Authentication

JSON request body

JSON response

Personalization parameters

Rate limits

Error handling

Getting started checklist

Examples and advanced use cases

Goal

Prerequisites

Step 1: Create the Data Feed

Step 2: Create the email template

Step 3: Attach the Data Feed and trigger the email

Step 4: Manage coupon redemption and tracking

Complete workflow example

Testing

FAQ

My Data Feed values are not appearing in the message. What should I check?

Why are messages sending slowly?

Why are some recipients not getting messages?

Can I use more than one Data Feed in a template?

Are Data Feeds available for push notifications or SMS?

What happens if my API is down when the message sends?

Related pages