How to track webinar registration to attendance for Reddit Ads

Architecture

The exact event sequence

Five stages. The gap between stages two and three is days, which is short enough to stay inside every import window and long enough to break cookie-based approaches. The identifier has to survive all of them.

1. Step 1

   Ad click

   Identifier captured on landing and written into the registration.

2. Step 2

   Registered

   The form event. Cheap, plentiful, and a weak predictor on its own.

3. Step 3

   Attended

   Days later, from the platform's webhook. This is the event worth optimizing toward.

4. Step 4

   Watched past a threshold

   Where the platform reports it — a much stronger signal than merely joining.

5. Step 5

   Attendance sent back

   Uploaded against the original click, so bidding learns which channels produce people who show up.

Diagnostic sequence

What's specific to Reddit Ads

The funnel logic above is the same wherever you advertise. These are the parts that change because it's Reddit Ads.

1. 1

   Click identifier: the rdt_cid click identifier

   Reddit appends rdt_cid to your landing page URL, and the Reddit Pixel keeps its own identifier in the _rdt_uuid cookie. Reddit's audience is unusually privacy-aware — ad-blocker and tracker-blocker usage on Reddit traffic runs well above the web average — so the share of visits where the pixel never loads at all is higher here than on any other network in this list. The URL parameter is the identifier that survives; the cookie often does not.

2. 2

   Import mechanism: the Conversions API

   Server events posted to Reddit's Conversions API with the click identifier and hashed customer information. Reddit's implementation is younger than Meta's and its documentation moves — confirm the current endpoint, event names and required fields against Reddit's own developer docs rather than an integration blog post.

3. 3

   Deduplication

   The pixel and the Conversions API event must carry the same conversion identifier for the same action. Because so much Reddit traffic never runs the pixel at all, a lot of accounts skip the pixel entirely and send server-side only — which is a legitimate choice here in a way it rarely is elsewhere, and it removes the deduplication problem completely. Decide deliberately rather than running both and hoping.

4. 4

   Window and timing

   Reddit's default attribution windows are shorter than Meta's and are configurable. Check what your account is set to before reconciling anything, and verify the accepted event-freshness limit for server events against Reddit's current documentation.

5. 5

   The Reddit gotcha

   Reddit converts on a delay and on trust. People read a thread, leave, think about it, and come back through a branded search a week later — which is a genuine Reddit-driven conversion that Reddit will never be credited for and Google will happily claim. If Reddit is judged purely on last-click inside its own window, it will always look worse than it is. Build the measurement, then argue about attribution with that context on the table.

Source-of-truth validation

How to prove the chain works

One real journey, followed all the way, then a reconciliation. Neither on its own is enough.

• A live Reddit ad clicked, and the identifier confirmed present on the landing URL.
• The same identifier confirmed on the registrant record in your webinar platform and CRM after a full real journey through every step.
• Attendance sent back confirmed arriving at Reddit Ads, verified by the events received and matched in Reddit Ads Manager, reconciled against your own records.
• Your webinar platform's attendance records reconciled against Reddit Ads per record over a fully closed window.
• The same reconciliation repeated 30 days later.

Straight talk

When this doesn't apply to you

Worth checking before you build anything, because two of these are common and both mean the work isn't worth doing.

• If your webinars are evergreen and on-demand, there's no scheduled attendance event to send. That's closer to a content-consumption funnel and wants a different treatment.
• If you are not running Reddit at meaningful spend, skip it. And if your Reddit strategy is organic community presence rather than ads, none of this applies — that traffic has no click identifier by definition.
• If your cycle from click to attendance sent back regularly exceeds the import window, the final event can't drive bidding whatever you build. Optimize toward registration with a qualification flag instead and use the later data for budget decisions rather than for bidding.
• If almost none of your registrant records carry a click identifier today, that's the whole project. Fix capture first — the import is the easy half and no tooling rescues a record with nothing to reference.