---
title: Track Event for the Python SDK
slug: feature-experimentation/docs/track-event-python
docTags: 
createdAt: 2026-08-05T20:39:57.000Z
---

Use the decide methods to return feature flag decisions for a user. Each decision includes whether the flag is enabled and which variation the user receives.

## Decide

Returns a decision for a specific feature flag and user.

## Version

SDK 3.7 and higher. See [Minimum version support](docId:2shbZfPCkPAZ0mlZpL1TU).

## Description

Use this method to track events across multiple flag rules for a user. You should make only one `track_event` call per conversion (user action), even if many rules measure the conversion.

You call the `track_event` method on a user. For information about the user object, see [OptimizelyUserContext for the Python SDK](docId\:UGnzh86pPS0MtU91FSSlQ).

:::hint{type="warning"}
The attributes passed to `track_event` are *only* used for [results segmentation](docId:_K6n7h_MZ8b0xn6yWPrrq) on the [Optimizely Experiment Results page](docId\:mrUblIuNVOZc1dvjWdsbw).
:::

## Parameters

- `eventKey` (required) – String – The key of the event to be tracked. This key must match the event key provided when the event was created [in the Optimizely app](docId\:Bf3o37J3IJTUuVR7GshGd) or [REST API](docId\:NxpGs0D4LibV6Jp26feiJ).
- `eventTags` (optional) – Map – A map of key-value pairs specifying the [reserved tag keys](docId\:TPYh_YgbEQNnWIXKthzhl) names and their corresponding values for this particular event occurrence. `eventTags` are contextual metadata about [conversion events](docId\:onBazDzYYz526tL9aQF0s). For example, revenue, load time, or total value. The following are available tag keys:
  - `revenue` – An integer value that is used to track the revenue metric for your experiments, aggregated across all conversion events. `revenue` is recorded in cents.
  - `value` – A floating point value that is used to track a custom value for your experiments. Use this to pass the value for numeric metrics.
  - `$opt_event_properties` –   A map of default and custom event properties and their values.

See [reserved event tags](docId\:TPYh_YgbEQNnWIXKthzhl).

## Returns

This method sends conversion data to Optimizely Feature Experimentation. It does not provide return values.

## Example

```python
from optimizely import optimizely 
optimizely_client = optimizely.Optimizely(sdk_key='123456') 
user = optimizely_client.create_user_context("user123", {"logged_in": True}) 


# Event properties
properties = { 
  "category": "shoes", 
  "color": "red"
} 

# Event tags
tags = { 
  "revenue": 10000,
  "value": 100.00, 
  "$opt_event_properties": properties 
} 

# track_event(eventKey (required), eventTags (optional)
user.track_event("my_purchase_event_key", tags) 
```

## Side effects

Additional Feature Experimentation functionality may be triggered by using this method.

### Conversions

Calling this method records a conversion and attributes it to the variations that the user has seen. See [How Optimizely Experimentation counts conversions](docId\:onBazDzYYz526tL9aQF0s).

You can create [metrics](docId\:e2qGf29S6pO8SW90_IVuH) on this conversion event and add metrics to experiments even after the conversion is tracked. See [Events: Tracking clicks, pageviews, and other visitor actions](docId\:puGm9z4XkEG5PDkyaNmlA).

:::hint{type="danger"}
This method does not track events if the event key is invalid.

Changing the traffic allocation of running experiments affects how conversions are recorded and variations attributed to users. See [Why you should not change a running experiment](docId\:IsU8ejnD3mrkAia2mtIOA).
:::

### Notification listeners

Accessing this method triggers a call to the [track notification listener](docId\:PaUUiwg7zYOguMb_HrFGN).

:::hint{type="danger"}
This method does not call the `TRACK` notification listener if the event key is invalid.
:::

## Source files

The language and platform source files containing the implementation for Python are available on [GitHub](https://github.com/optimizely/python-sdk/blob/master/optimizely/optimizely.py).