---
title: Log event notification listener
slug: feature-experimentation/docs/log-event-notification-listener
docTags: 
createdAt: 2026-08-05T20:40:01.000Z
---

The log event notification listener is similar to the [track notification listener](docId\:PaUUiwg7zYOguMb_HrFGN) but provides more granularity. You can use it to inspect and audit what data was sent to Optimizely in a given event batch, and when the batch was sent.

## Parameters

The following table shows the information provided to the log event listener when it is triggered:

| Parameter     | Type      | Description                                                                                                                                                                                          |
| ------------- | --------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **log event** | Log Event | A \`LogEvent\` object containing a batch of conversion and decision events. Created by the \`EventFactory\` whenever the event processor produces a batch. For information, see the following table. |

### Log Event

The `LogEvent` object represents the batch of decision and conversion events passed to the event dispatcher.

| Object                                | Type   | Description                                                                                                                 |
| ------------------------------------- | ------ | --------------------------------------------------------------------------------------------------------------------------- |
| **http verb** \*Required (non null)\* | String | The HTTP verb to use when dispatching the log event. Can be \`GET\` or \`POST\`.                                            |
| **url**\ \*Required (non null)\*      | String | URL to dispatch log event to.                                                                                               |
| **params**\ \*Required (non null)\*   | Dict   | The event batch. Contains all events in the batch, including a list of visitors and their associated \`UserEvent\` objects. |
| **headers**                           | Dict   | Request headers.                                                                                                            |

## Examples

For code examples, see the following SDK documentation on notification listeners:

- [Android SDK](docId:7YBxDk67DRrkZf3FbyIJ-)
- [C# SDK](docId\:Ee1jEssfFPw17lJyVP9m9)
- [Flutter SDK](docId\:HK9-OAb_ZXtphGmvU8Uga)
- [Go SDK](docId\:t5MKaa3LIkBM5ovyv7XYn)
- [Java SDK](docId\:CaIM2oX09aWIajqNcz0Ct)
- [JavaScript SDK](docId\:iYEM6cOT51dak_I7ellNY) – SDK versions 6.0.0 and later.
- [JavaScript (Browser) SDK](docId\:qykXcla2WZgtq4LHGWSfU) – SDK versions 5.3.5 and earlier.
- [JavaScript (Node) SDK](docId\:qykXcla2WZgtq4LHGWSfU) – SDK versions 5.3.5 and earlier.
- [PHP SDK](docId\:B3h4PE4eFEjjhKpiue0N_)
- [React SDK](docId\:eyOn7CmG5jWwB3vIm7mt9)
- [React Native SDK](docId:04d5tm_qqBTXKMKKnh1rZ)
- [Ruby SDK](docId:0pKUE1RjpxrcY4xgjh1Y3)
- [Python SDK](docId\:EjbZOLZ2M6aN5QW0T1Ufy)
- [Swift SDK](docId\:olc5F0M6g6El8a0puGbRX)