Adding Event Properties to Existing Mixpanel Events

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You cannot directly modify or add properties to events that have already been recorded in Mixpanel. However, Mixpanel offers a feature called Borrowed Properties that allows you to "borrow" a property from one event and use it in the analysis of another event—even if that property was not originally tracked on the event. This is done at query time in the Mixpanel UI, so it does not actually change the stored event data, but it enables you to analyze events as if the property had always been there.For example, if you want to break down a “Completed Purchase” event by a property that only exists on a prior “Add to Cart” event, you can use Borrowed Properties to do this analysis without re-tracking or modifying historical data. This works retroactively and does not require engineering changes to your implementation. However, it is not a substitute for thoughtful tracking plans and does not physically alter the event data in your project Introducing Borrowed Properties | A leap forward in the product analytics data model.If you need to actually change or add properties to historical events in the data store itself, the knowledge sources do not mention any way to do this in Mixpanel.

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Based on the knowledge sources, it is not possible to directly alter or add properties to events that have already been recorded in Mixpanel through the standard event tracking methods. Events in Mixpanel are fundamentally immutable once ingested Build Your Tracking Strategy.However, there is an exception if you are using Mixpanel's Warehouse Connectors with the Mirror mode. Mirror allows you to sync changes from your data warehouse—including updates to historical events—so that changes in your warehouse (such as adding a new property to past events) are reflected in Mixpanel. This is achieved by syncing changes via change data capture (CDC), effectively overcoming the traditional immutability of events in Mixpanel Introducing Mirror | Star schema to event schema.In summary: - Standard event tracking: You cannot alter already recorded events. - Warehouse Connectors (Mirror mode): You can update historical events by syncing changes from your warehouse.If you are not using Warehouse Connectors with Mirror, you cannot alter events already recorded in Mixpanel.

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