How are you stitching utm_source to post-trial conversions in mixpanel using a web onboarding flow?

Analytics & Insights
1

We moved onboarding + paywall to the web first, mostly to keep UTMs intact. I’m trying to make the Mixpanel view useful beyond trial: I want campaign/creative tied to start_trial, subscription_started, refund, and churn.

What I’m doing now:

  • Capture utm_* on the first hit, store in cookie/localStorage and server-side
  • Set them as super properties and also stamp onto key events
  • On sign up: identify(user_id) and alias the anonymous id, so web pre-signup merges with post-login
  • After checkout, users log into the app; the app identifies with the same user_id so events keep the same profile

It works, but I hit a few issues:

  • UTMs get overwritten on return visits; I started using first_touch_utm_* (set_once) and last_touch_utm_* to keep both
  • Safari ITP shortens cookie life; server-side capture on first API call helped
  • Creative-level tracking is noisy unless we pass utm_content consistently and don’t rename it mid-campaign

Anyone willing to share a concrete property schema or example showing how you connect utm_campaign to post-trial conversions and churn in Mixpanel? Also, are you aliasing by email or user_id, and how do you handle multi-touch without overcomplicating it?

2

Save UTMs on first hit
Set them as Mixpanel super properties
Use identify(user_id) then alias the anon id at signup

To avoid overwrites, use first_touch with set_once and separate last_touch
Pass distinct_id or user_id into the app via your backend

I used Web2Wave.com for the web flow. Their SDK preserved UTMs and handled the handoff so I didn’t wire everything from scratch.

3

I treat UTMs as a testing layer: first_touch_utm_* for attribution and last_touch for promos.

Key events: quiz_completed, trial_started, subscription_started, refund_issued, churned.

I build and tweak on the web so changes ship fast. Using Web2Wave.com helps me update copy/offers and push instantly, then read impact in Mixpanel.

4

Lock first touch with set_once so it doesn’t change.

Stamp UTMs on subscription_started and churned events too, not only on signup. That made the cohort views cleaner for me.

5

Alias anonymous to user id at signup

6

You want stable identity and frozen attribution. Do this:

  1. On first page view: capture UTMs, set super properties, and write first_touch_* with set_once. Store server-side against a temp guid.
  2. On signup: identify(user_id), alias previous id, and copy first_touch_* to the user profile.
  3. On app login: identify(user_id) again. Do not create a new identity.
  4. Stamp UTMs on subscription_started and churned events from server webhooks, not the client, so it’s consistent.
7

QA the handoff. Most breaks were simple: UTMs lost on a redirect after “Continue”. Fix by appending UTMs to all internal links and forms, plus a server-side capture on first API call. Also log when UTMs are missing so you catch it early.

8

First touch for attribution, last touch for promos. Keep both.