***Non-critical Plugins**: Analytics.js can start event delivery before this plugin finishes loading. This means your plugin can fail to load independently from all other plugins. For example, every Analytics.js destination is a non-critical plugin. This makes it possible for Analytics.js to continue working if a partner destination fails to load, or if users have ad blockers turned on that are targeting specific destinations.

Non-critical plugins run through a timeline thatexecute in order of insertion based on the entry type. Segment has these five entry types of non-critical plugins:

Non-critical plugins run through a timeline thatexecutes in order of insertion based on the entry type. Segment has these five entry types of non-critical plugins:

Type | Details

---- | -------

`before` | Executes before event processing begins. These are plugins that run before any other plugins run. <br><br>For example, validating events before passing them along to other plugins. A failure here could halt the event pipeline. <br><br> See the example of how Analytics.js uses the[Event Validation plugin](https://github.com/segmentio/analytics-next/blob/master/src/plugins/validation/index.ts) to verify that every event has the correct shape.

`enrichment` | Executes as the first level of event processing. These plugins modify an event. <br><br> See the example of how Analytics.js uses the[Page Enrichment plugin](https://github.com/segmentio/analytics-next/blob/master/src/plugins/page-enrichment/index.ts) to enrich every event with page information.

`before` | Executes before event processing begins. These are plugins that run before any other plugins run. <br><br>For example, validating events before passing them along to other plugins. A failure here could halt the event pipeline. <br><br> See the example of how Analytics.js uses the[Event Validation plugin](https://github.com/segmentio/analytics-next/blob/master/src/plugins/validation/index.ts){:target="_blank"} to verify that every event has the correct shape.

`enrichment` | Executes as the first level of event processing. These plugins modify an event. <br><br> See the example of how Analytics.js uses the[Page Enrichment plugin](https://github.com/segmentio/analytics-next/blob/master/src/plugins/page-enrichment/index.ts){:target="_blank"} to enrich every event with page information.

`destination` | Executes as events begin to pass off to destinations. <br><br> This doesn’t modify the event outside of the specific destination, and failure doesn’t halt the execution.

`after` | Executes after all event processing completes. You can use this to perform cleanup operations. <br><br>An example of this is the[Segment.io Plugin](https://github.com/segmentio/analytics-next/blob/master/src/plugins/segmentio/index.ts) which waits for destinations to succeed or fail so it can send it observability metrics.

`after` | Executes after all event processing completes. You can use this to perform cleanup operations. <br><br>An example of this is the[Segment.io Plugin](https://github.com/segmentio/analytics-next/blob/master/src/plugins/segmentio/index.ts){:target="_blank"} which waits for destinations to succeed or fail so it can send it observability metrics.

`utility` | Executes only with manual calls such as Logging. <br><br>These are plugins that change the Analytics 2.0 functionality. Utility plugins run outside of the event pipeline, and only execute once.

awaitwindow.analytics.register(identityStitching())

You can view Segment's[existing plugins](https://github.com/segmentio/analytics-next/tree/master/src/plugins) to see more examples.

You can view Segment's[existing plugins](https://github.com/segmentio/analytics-next/tree/master/src/plugins){:target="_blank"} to see more examples.

Registering plugins enable you to modify your analytics implementation to best fit your needs. You can register a plugin using this: