Triggers: what starts a workflow

A trigger is the event that starts a run. The big split is how the tool finds out the event happened. Either it asks, or the app tells it. That's it.

What you need to know first

• Which app holds the event, such as a form, a spreadsheet or a mailbox.
• Whether that app can send a notification when something changes, or only answers when asked.
• How fast you need the run to start.

Polling triggers

Think of checking a mailbox on a timer. Zapier describes polling as the tool asking your app for data every so often.¹

The app sends back its latest items. Zapier then compares each item's unique ID to IDs it has seen before. A new ID starts a run. Nothing new? It waits and asks again.¹

How long the tool waits between questions depends on the plan. Zapier's help page listed these on 4 November 2026.¹

Plans and intervals change, so check the maker's page before you rely on a number. The same page says most triggers are polling triggers.¹

Instant triggers

An instant trigger flips this around. The app pushes the news, and nobody has to ask. In Zapier's words, the app sends the new data by itself each time the event happens.¹

The push usually travels as a webhook. Wikipedia explains that the site where the event happened sends an HTTP request to a web address you've set up for that purpose.²

Testing catches people out. Make notes that an instant trigger needs incoming info to run. Until data arrives, it just waits. So cause the event yourself, such as submitting the form, and then look at what the module received.³

Schedules

Some workflows don't wait for an event. They run on the clock. n8n's Schedule Trigger node runs workflows at fixed intervals and times.⁴ A weekly report fits that. A new-lead alert doesn't.

Things to know before you switch one on

• You usually can't swap the type. Zapier says the trigger type is fixed and you cannot change it.¹
• Old data is skipped. A Zap won't trigger for old data, including data created before it was turned on.¹
• Loops can burn through your allowance. If a workflow writes back to the same app it watches, the update can retrigger it and create an infinite loop that rapidly consumes tasks.¹
• Waiting costs nothing in Zapier. Triggers never use tasks, and neither do the polls.⁵

Make counts differently. Its trigger modules only run once to check for or retrieve data, however many items come back.⁶ The counting rules of all three makers sit together in the last page of this set.

Once a trigger fires, the first step takes over. Actions and steps covers what happens next.