Custom events

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How-to guide
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Dynatrace allows you to send custom events to track business metrics or application-specific data. You can also enrich all events with additional context using 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

Use sendEvent() to report custom events with properties. Property keys must be prefixed with event_properties..

import 'package:dynatrace_flutter_plugin/dynatrace_flutter_plugin.dart';

double value = 149.99;

// Using constructor
Dynatrace().sendEvent(EventData(
  duration: 250,
  eventProperties: {
    'event_properties.checkout_step': 'payment_confirmed',
    'event_properties.cart_value': value,
    'event_properties.item_count': 3,
  },
));

// Using addEventProperty method
final event = EventData(duration: 250)
  ..addEventProperty('event_properties.checkout_step', 'payment_confirmed')
  ..addEventProperty('event_properties.item_count', 3);
if (value > 0) {
  event.addEventProperty('event_properties.cart_value', value);
}

Dynatrace().sendEvent(event);

Property naming rules

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

Event modifiers

Event modifiers allow you to intercept and modify all events before they are sent to Dynatrace. Use them to add common properties, redact sensitive information, or filter events.

Add an event modifier

import 'package:dynatrace_flutter_plugin/dynatrace_flutter_plugin.dart';

Dynatrace().addEventModifier((event) {
  // Add experiment tracking to all events
  event['event_properties.experiment_id'] = 'checkout_flow_v2';
  event['event_properties.variant'] = 'treatment_a';
  return event;
});

Remove event modifiers

import 'package:dynatrace_flutter_plugin/dynatrace_flutter_plugin.dart';

// Define the modifier
Map<String, dynamic>? myModifier(Map<String, dynamic> event) {
  event['event_properties.custom'] = 'value';
  return event;
}

// Add the modifier
Dynatrace().addEventModifier(myModifier);

// Remove when no longer needed
Dynatrace().removeEventModifier(myModifier);

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 examples

Filter events

Return null to discard an event:

import 'package:dynatrace_flutter_plugin/dynatrace_flutter_plugin.dart';

Dynatrace().addEventModifier((event) {
  // Filter out events from test users
  if (event['event_properties.is_test_user'] == true) {
    return null; // Discard this event
  }
  return event;
});

Redact sensitive data

import 'package:dynatrace_flutter_plugin/dynatrace_flutter_plugin.dart';

Dynatrace().addEventModifier((event) {
  // Redact user IDs from URLs
  if (event.containsKey('url.full')) {
    event['url.full'] = event['url.full']
        .toString()
        .replaceAll(RegExp(r'/users/\w+/'), '/users/{id}/');
  }
  return event;
});

Add feature flags

import 'package:dynatrace_flutter_plugin/dynatrace_flutter_plugin.dart';

void setupFeatureFlagTracking(Map<String, bool> featureFlags) {
  Dynatrace().addEventModifier((event) {
    for (final entry in featureFlags.entries) {
      event['event_properties.ff_${entry.key}'] = entry.value;
    }
    return event;
  });
}

Conditional event enrichment

import 'package:dynatrace_flutter_plugin/dynatrace_flutter_plugin.dart';

void setupConditionalEnrichment() {
  Dynatrace().addEventModifier((event) {
    // Only enrich HTTP events
    if (event.containsKey('http.request.method')) {
      event['event_properties.api_client'] = 'flutter_app';
      event['event_properties.api_version'] = 'v2';
    }

    // Only enrich error events
    if (event.containsKey('exception.type')) {
      event['event_properties.error_context'] = 'user_session';
    }

    return event;
  });
}

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