Google Analytics 4 has strict rules for event naming andrequire you to adhere to those requirements in order to successfully send events.

Google Analytics 4 has strict rules for event naming andrequires you to adhere to those requirements in order to successfully send events.Segment will replace all spaces with underscores to ensure the event name adheres to Google's[event naming rules](https://support.google.com/analytics/answer/13316687?hl=en&ref_topic=13367860&sjid=2167389739796023681-NA#zippy=%2Cweb){:target="_blank"}. As a result, you will see custom events snake cased in Google Analytics 4.

Per Google's documentation on[event naming](https://support.google.com/analytics/answer/13316687?hl=en&ref_topic=13367860&sjid=2167389739796023681-NA#zippy=%2Cweb){:target="_blank"}, follow these rules when choosing a name for your event:

Per Google's documentation, follow these rules when choosing a name for your event:

- Event names are case sensitive. For example, my_event and My_Event are distinct events.

- Event names can include English and non-English words and letters.

- Do not use reserved prefixes and event names.

- Event names must start with a letter. Use only letters, numbers, and underscores. Don't use spaces.

Google Analytics 4does not accept custom event names that include spaces. Segment replaces spaces inthe Event Namein the Custom Eventaction with an underscore. As a result, you willsee custom events snake cased in Google Analytics 4.

Google Analytics 4is also case sensitive. If you would like all event names to be lowercase, usethe`LowercaseEvent Name` settingin the Custom Eventmapping. If this setting is disabled, Google willtreat event names with different casing as distinct events.

Google Analytics 4 is also case sensitive. If you would like all event names to be lowercase, use the`Lowercase Event Name` settinginthe Custom Event action. If this setting is disabled, Googlewilltreat event names with different casing as distinct events.

Custom events do not appearinmost standard reports; youwillneed to set up custom reports for meaningful analysis.