Clarification Needed: First Seen Property Truncation in Mixpanel

·Sep 05, 2025 02:33 PM·

I've just noticed that the First Seen property is truncated to the last 5 years, and that maybe it should be better described as First Seen in the last 5 years? Was it intended to work this way, or is this an unexpected side effect of Mixpanel's data retention policy?

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Julianne Bozzini
APP
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Hi Vlad- Julianne from Mixpanel Support here! You're observation is spot on. The 'First Seen' property in Mixpanel is computed based on the oldest event for a user. With a 5-year data retention policy, events older than 5 years are deleted, so the property does represent the first time the user was seen in the last 5 years.

Julianne Bozzini
APP
·
·
Hi Vlad- Julianne from Mixpanel Support here! You're observation is spot on. The 'First Seen' property in Mixpanel is computed based on the oldest event for a user. With a 5-year data retention policy, events older than 5 years are deleted, so the property does represent the first time the user was seen in the last 5 years.