Custom events

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How-to guide

Dynatrace supports custom events to track user interactions, business metrics, and application-specific signals. Events can also be enriched before they are sent by applying event modifiers.

Event and session properties

Configure event and session properties

Before you can send event or session properties from your application, you must first define them in the Dynatrace web UI. Any properties that are not pre-configured will be discarded.

To define a new property

In Experience Vitals, select the frontend for which you want to add the property.
Select the Settings tab, then choose Event and session properties.
Select Add under either Defined event properties or Defined session properties, depending on the type of property you want to create.
In the Field name box, enter a name for your property (for example, cart.total_value).
Optional To make the field name case-insensitive, turn on Field name validation should be case-insensitive.
From the Datatype list, select the appropriate data type for your property: string, boolean, or number.

Dynatrace automatically prefixes your field name with event_properties. or session_properties. based on the property type you selected. For example, a field name of cart.total_value will become event_properties.cart.total_value.

Send custom events

Custom events are reported using Dynatrace.sendEvent(...) with optional duration and event properties.

Consider basic usage

// Simple event
Dynatrace.sendEvent(EventData())

// Event with duration (in milliseconds)
Dynatrace.sendEvent(EventData().withDuration(150))

Add event properties

Custom properties provide context for reported events. Property keys must be prefixed with event_properties..

Dynatrace.sendEvent(
    EventData()
        .withDuration(250)
        .addEventProperty("event_properties.checkout_step", "payment_confirmed")
        .addEventProperty("event_properties.cart_value", 149.99)
        .addEventProperty("event_properties.item_count", 3)
)

Property naming rules

For naming rules and limits, see Event and session properties.

Event modifiers

Event modifiers intercept events before they are sent. They can be used to add common properties, redact sensitive information, or filter events.

On Android, modifiers operate on a JSONObject representation of the event.

Add an event modifier

val modifier = EventModifier { event ->
    // Add build variant context to all events
    event.put("event_properties.build_type", BuildConfig.BUILD_TYPE)
    event.put("event_properties.flavor", BuildConfig.FLAVOR)
    event
}

Dynatrace.addEventModifier(modifier)

Filter events

Returning null discards an event.

val modifier = EventModifier { event ->
    // Events happening on the com.example.MainActivity activity will be dropped.
    if (event.optString("view.detected_name") == "com.example.MainActivity") {
        return@EventModifier null
    }
    event
}

Dynatrace.addEventModifier(modifier)

Redact sensitive data

val modifier = EventModifier { event ->
    // Redact user IDs from URLs
    val url = event.optString("url.full", null)
    if (url != null) {
        val redactedUrl = url.replace(Regex("/users/\\w+/"), "/users/{id}/")
        event.put("url.full", redactedUrl)
    }
    event
}

Dynatrace.addEventModifier(modifier)

Remove event modifiers

// Store the modifier when adding it
val modifier = EventModifier { event ->
    event.put("event_properties.custom", "value")
    event
}

Dynatrace.addEventModifier(modifier)

// Remove when no longer needed
Dynatrace.removeEventModifier(modifier)

Modifier limitations

Event modifiers have restrictions on which fields can be modified to ensure data integrity.

Modifiable fields

The following fields can be modified or added:

event_properties.*—event properties.
session_properties.*—session properties (only on session property events).
url.full—complete request URL.
exception.stack_trace—exception stack traces.

All other fields are read-only and can't be modified. The original values are preserved.

Important considerations

Thread safety—modifiers may be called from any thread; ensure your code is thread-safe.
Performance—keep modifiers efficient; they run for every event.

Modifier example

Conditional event enrichment (example)

The following example shows how to enrich only specific event types. It adds context to HTTP events (for API segmentation) and to error events (for faster triage).

fun setupConditionalEnrichment(apiClientName: String) {
    val modifier = EventModifier { event ->
        // Add context only for HTTP events
        if (event.optBoolean("characteristics.has_request")) {
            event.put("event_properties.api_client", apiClientName)
            event.put("event_properties.api_kind", "backend")
        }

        // Add context only for error events
        if (event.optBoolean("characteristics.has_error")) {
            event.put("event_properties.triage_owner", "mobile")
            event.put("event_properties.triage_severity", "error")
        }

        event
    }

    Dynatrace.addEventModifier(modifier)
}

Web request performance—HTTP event modifiers.
Error and crash reporting—exception events.
Configuration—agent configuration.