Types of triggers in Zaps – Zapier

A trigger is an event within an app that starts a Zap. Once you’ve turned your Zap on, Zapier will check for that trigger event. Zaps can be triggered in two ways: through a regular polling event or instantly through webhooks.

## Trigger types

Each app on Zapier has an [API](https://zapier.com/learn/apis/) that allows other apps, like Zapier, to view and edit its data. Each trigger on Zapier connects to that app’s API to get new data about trigger events. The type of trigger is defined by each app’s API. Some apps support polling triggers, others support instant triggers, and some support both.

![alt](https://cdn.zappy.app/865301ac734dd961be3233491b8f1019.png)

![actionEdit icon](https://cdn.zapier.com/storage/photos/649a3c82786155ec1f844e1e870a74bf.png) Example

A trigger event is the data that the trigger is meant to receive, such as:

*   A new spreadsheet row was created in your spreadsheet app.
*   A new lead was created in your CRM app.
*   A new subscriber was added to a list in your email marketing app.

### Polling triggers

Most APIs require apps to ask for new data periodically. This is called [polling](https://zapier.com/learn/apis/chapter-7-real-time-communication/) for new data. In Zapier, polling triggers ask the API for all recent data. It then uses a process called [deduplication](https://zapier.com/help/create/basics/understand-data-deduplication-in-zaps) to check if any of that data is new. If it is, the Zap runs. If not, it waits for a set period, then asks again, and so on.

The majority of triggers are polling triggers. They check (or poll) the app for data at regular intervals. The Zap will [check if there's new data](https://help.zapier.com/hc/en-us/articles/8496260269965) by comparing the item's unique ID to IDs it's already received before.

The interval it uses to check for data depends on your [Zapier plan](https://zapier.com/pricing). The shorter the interval, the faster new data will come through the Zap.

### Instant triggers

Some APIs automatically send new data as those trigger events occur, using [webhooks](https://zapier.com/learn/apis/chapter-7-real-time-communication/). These are called "instant" triggers. Webhooks are automated notifications sent between apps. Whenever there is new data, the app will notify Zapier as soon as that data is added in the app.

In Zapier, instant triggers wait for the app to send new data automatically. Zapier does not have to ask the API if there’s any new data. When it receives new data, the Zap runs. Zaps with instant triggers are labeled "Instant" in the Zap editor.

## Testing triggers to return test records

When you test a trigger while editing a Zap, Zapier will attempt to find a recent item from your trigger app that you can use as a test record to build your Zap. 

When you test a polling trigger, Zapier will:

*   Poll the app for data.
*   Display the three most recent trigger items found in the poll. 

When you test an instant trigger, Zapier will:

*   Begin listening for new data from your app.
*   Display up to three of the most recent trigger items that were created after Zapier begins listening for new data from your app.

![miscEye icon](https://cdn.zapier.com/storage/photos/335619ab6472fe1fefab18d493cb39bf.png) Note

For instant triggers, Zapier can only load test records for data that was created in your app after you first open the Test section in your trigger step.

## Limitations

*   You cannot change a trigger's type.
    *   The trigger type is defined by the app’s API.
    *   Most APIs provide ways to poll for data.
    *   To use instant triggers, an app must offer [webhooks](https://zapier.com/blog/what-are-webhooks/), which send new data to a Zap automatically without polling.
*   Zaps will only trigger for new data.
    *   It will not trigger for old data, including data that was created in your app before the Zap was turned on.
    *   If you need to transfer existing data, use Zapier’s [Transfer](https://help.zapier.com/hc/en-us/articles/8496274335885) feature.

Learn more about how to [set up a Zap trigger](https://help.zapier.com/hc/en-us/articles/8496288188429).