Destination Filters

Destination Filters allow you to control the data flowing into each specific destination, by conditionally preventing data from being sent to cloud-mode destinations. You can filter out entire events, or just specific fields in the properties, traits, or in the context of your events.

With Destination Filters, you can:

• Control your event volume by sampling or dropping unnecessary events for specific destinations.
• Manage PII (personally identifiable information) by blocking fields from reaching certain destinations.
• Increase the relevance of the data in your destinations by removing unused or unwanted data.
• Prevent test or internally-generated events from reaching your production tools.

Destination Filtering Limitations

• Destination Filters can only be applied to Cloud-mode (“server-side”) streaming destinations. Device-mode destinations are not supported.
• You cannot apply Destination Filters to Warehouses or S3 destinations.
• Each filter can only apply to one source-destination pair.

If you have a compelling use case for these unsupported options, contact us.

Destination Filters API

The Destination Filters API provides even more power than the Destination Filters settings in the Segment dashboard. You can create complex filters that are conditionally applied using Segment’s “Filter Query Language” (FQL).

The Destination Filters API offers four different types of filters:

1. drop_event: Do not send matched event to the destination.
2. sample_event: Send only a percentage of events through to the destination.
3. whitelist_fields: Only send whitelisted properties to destination.
4. blocklist_fields: Do not send blocklisted properties to destination.

Read more in the Destination Filters API docs.

Examples

PII Management

Example: Remove email addresses from context and properties:

Property-level whitelisting is available using our API. Use this to do things like only send certain traits you know have no PII to a destination, and block all other traits in the context or property fields.

Control Event Volume

Example: Only send user signed up and demo requested events:

Cleaner Data

Example: only send events - only send track calls to Google Analytics:

Remove Internal and Test Events From Production Tools

Example: Do not send events when email contains @segment.com:

Example: Do not send events when the Order Completed and properties.email contain @segment.com.

Sample a Percentage of Events

Example: Randomly sample video heartbeat events:

Note: Random sampling can currently only be created using our API: Full API docs here

Drop Events

This video shows an example of filtering events being sent to a destination based on the name of the event.

Important Notes

Conflicting settings

Some destinations offer settings that also allow you to filter data. For example, the Facebook App Events destination allows you to map Screen events to Track events. Because Destination Filters are evaluated and applied before the Destination settings are applied, they can conflict with your settings.

In the example in the video above, if you have a Destination Filter that only allows Track events and you have the “Use Screen Events as Track Events” setting enabled, Track events are dropped, but Screen events are still processed and are transformed by the destination settings into a Track event - after the filters.

Error handling

We make every effort to ensure that Destination Filters handle unexpected situations gracefully. For example, if you use the contains() FQL function on a field and that field is null, we return false instead of returning an error. If we can’t reasonably infer your intent, we log an internal error, and drop the event. We default to this behavior to prevent sensitive information, for example from a PII filter, from getting through.

Errors are not exposed in the Event Deliverability tab of your Destination. For help diagnosing unexpectedly missing events when using Destination Filters, contact us.

FAQ

Q: How does destination filters work with array properties?

Destination Filters can filter properties out of objects nested in an array. For example, you could filter out the price property of every object in an array at properties.products. You can also filter out an entire array from the payload. However, you cannot drop nested objects in an array, or filter properties out of a single object in an array.

Q: How many filters can I create?

You are currently limited to 10 filters per destination. If you need help consolidating filters or would like to discuss your use case, contact us!

Q: When will you support device-mode?

Device-mode destination filters for Web are currently in Early Access Preview.

contact us if you are interested in testing this feature.

Q: When will you support warehouses?

If you want to filter out events from warehouses, the best way to do that today is with the existing Selective Sync feature.

Q: I don’t see a “name” property at the top level of my events to filter on “event name”!

Generally, only Track calls have “name” properties, which corresponds to the “Event” field in an event.

Q: How can I find out when new filters have been added or removed from a destination?

The Activity Feed shows the action, date, and user who performed the action when a Destination Filter is created, modified, enabled, disabled, or deleted. You can also subscribe to notifications for any of these changes in the Activity Feed settings page.

Q: Why am I getting a permissions denied error when trying to save a filter?

Anyone with read access on the source can view and test filters, but only users with write access can edit filters.

Q: How can I test that my filter is working?

Use the Destination Filter tester (in the destination filter set up screens) to test if you are filtering out the right events. Filtered events still show up in the schema page, but are not counted in the Event Deliverability graphs.