StealthSeminar has a named leave webhook. Is that the same as a usable one?
No, and this is the platform where the difference between those two things is easiest to see — which is why it is worth a page of its own.
StealthSeminar documents leaveBefore — the only named leave webhook we found outside Zoom. No vendor document says how quickly it fires, and it is parameterised by a minute threshold, so you configure “tell me if they leave before minute N” rather than receiving a departure as it happens. An event whose timing nobody has published is not an event you can build a promise on, so our matrix records it as a no. Everything on the registration and arrival side, meanwhile, is unusually good.
Does StealthSeminar tell you when somebody leaves a session?
It tells you something, and the shape of that something matters more than its existence. The documented event is leaveBefore {minutes}— “Sent when an attendee leaves a webinar before a certain point”[1], with a sibling stayUntilthat fires when somebody watches past a point. Neither is a generic “this person just left” ping. You pick a minute mark in advance and get told about crossings of it.
That changes the integration design rather than tuning it. Approximating a live departure signal would mean standing up a rule at every minute mark you cared about and reconciling the results — and you would still not know how long after the event each POST arrives, because no document says. Zapier mirrors the same event as “Left Before…”, requiring a webinar and a minutes value[2], which is the same threshold shape wearing a friendlier name.
An undocumented timing is not a small gap — it is the whole question
One constraint runs the other way and is worth knowing before anything is wired up: StealthSeminar expects webhook endpoints to respond within ten seconds, and terminates the connection and counts the request failed if they do not. That is an obligation on our side, and it is the vendor’s published rule rather than a timing claim of ours — we publish none of those anywhere on this site.
What does StealthSeminar give us that most platforms do not?
A phone number with a name that admits what it is for, and a catalogue of events covering the parts of the sequence that actually move a show-up rate. Both are more valuable to this work than the missing departure signal, and neither gets mentioned when people compare platforms.
| What we need to know | The documented event | Usable? |
|---|---|---|
| Somebody registered | register — “Sent when an attendee registers for the webinar” | Yes |
| The session is approaching | fiveMinutesPrior through fortyEightHoursPrior — seven countdown events | Yes, though we run our own timer regardless |
| Somebody arrived | attend, plus joinAfter {minutes} for late arrivals | Yes — this is what stops us contacting someone already watching |
| Somebody left mid-session | leaveBefore {minutes} — threshold-based, firing time undocumented | No |
| Somebody never showed | missWebinar, plus attendReplay for the ones who watch later | Yes |
| A phone number to work with | sms_number — “Phone number for sending SMS reminders” | Yes, and named unambiguously |
The countdown events are a nice-to-have rather than a dependency. The call before the session — the piece with the strongest evidence behind it, where the registrant says in their own words when they will join and what they will be doing right before — runs off your session time and our own timer, so it behaves identically on every platform in the matrix. That is the micro-commitment, and it is the mechanism we sell rather than any particular channel.
Is any of this behind a plugin?
The API itself is not. StealthSeminar states plainly that “Yes we do offer an optional API. It is completely free”[4]. The attendance events are a different question: Zapier labels seventeen of StealthSeminar’s eighteen triggers “(Advanced plugin only)”[5], with new registrations the single exception. Plugins are priced separately by the vendor and we do not quote anybody else’s prices here.
Check which plan your attendance triggers sit on
The API being free does not settle it. If the events you need are behind the advanced plugin on your plan, that is a commercial question to answer with the vendor before an integration is designed around them, not after.
Confirm sms_number is being collected, and read the line beside it
The field exists and is well named, which is more than most platforms manage. What the registration form says next to it — who is being consented to, and whether an artificial voice is mentioned at all — is a legal question rather than a technical one, and it is settled before anything sends.
Decide what happens between registration and session
StealthSeminar's sessions are automated rather than scheduled, so the gap between somebody registering and the session starting can be minutes. That changes what is possible rather than how anything is configured, and it is the question worth reading before the integration questions.
One last thing, because it is the reason people arrive here from a search about evergreen attendance: the attendance percentages StealthSeminar publishes on its own marketing pages under the words “According to Statistics” trace back to a single 2019 consultant blog post that opens by calling them opinions. We do not repeat those figures, and the full trace — with both links, so you can follow it yourself — is on evergreen webinars, which is also the page that answers whether an automated funnel fits this at all.
Frequently asked questions
Because a named event and a usable one are different things. leaveBefore is parameterised by a minute threshold rather than reporting a departure as it happens, and no vendor document states how soon after the departure it is sent. The only honest description of that cell is “an event exists and nobody has published when it arrives”, and we are not going to sell a capability described that way.
Measuring it is a test webinar and an afternoon, so it is not the hard part. Publishing a number afterwards would be, because it would be our number about somebody else's platform with no vendor guarantee behind it, and it would change the day they changed their infrastructure without telling anyone. Mid-session exit is a no on every row of our matrix and we would rather leave it there.
The phone field. It is called sms_number, it is a standard registration field rather than an improvised custom question, and it arrives in the webhook payload as well. Several platforms in our matrix either have no phone field in the API at all or make you set one up per webinar by hand.
The vendor says so directly: “Yes we do offer an optional API. It is completely free.” The plugins are a separate matter — Zapier labels seventeen of eighteen StealthSeminar triggers as advanced-plugin-only — so what you can subscribe to depends on your plan rather than on the API itself.
We would not. The figures published there under the heading “According to Statistics” trace to a single 2019 consultant blog post that opens by presenting them as opinions. The trace, with both links, is on our evergreen webinars page. Your own funnel's number, measured over a few cycles, is worth more than any published benchmark.
You run a webinar. We come in and increase your show-up rate and your post-webinar sales, with our AI voice and SMS system — and you finally know why every registrant signed up. The whole table, with the date it was last checked, is on platforms, the automated-funnel question is answered on evergreen webinars. For contrast, Demio documents no webhooks at all, and BigMarker has the events but no phone field in its API. The way we ask to be measured is the pilot.
Founder & Operator, CallHush
Founder and operator of CallHush. The offer is one sentence: you run a webinar, and we increase your show-up rate and your post-webinar sales with an AI voice and SMS system. CallHush has no closed clients yet — the first engagement is a pilot run as a split of the client’s own registrant list, and nothing on this site is presented as a client result.
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