> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mailofly.com/llms.txt
> Use this file to discover all available pages before exploring further.

# The Doorbell Button

> The starting block that sounds the alarm whenever something happens in your app.

# The Doorbell Button (Trigger)

Every big show has an opening curtain! In Mailofly Automations, that opening curtain is **The Doorbell Button**.

Your automation sleeps peacefully until someone rings the doorbell. The moment the bell chimes, the automation leaps out of bed, opens the door, and starts running its steps!

***

## Setting Up Your Doorbell

Click on the top **Trigger** block on your canvas to open its side drawer:

### 1. Pick the Sound (Signal Name)

* Select an existing signal from your dropdown menu (like `user.signup` or `order.placed`).
* Or type in a brand-new signal name and press Enter to invent it instantly!

### 2. Check the Goodie Backpack (Expected Properties)

Signals can carry backpacks full of helpful details. In your trigger setup, you can list what items you expect:

* `first_name` (Words / String) — like "Maya"
* `items_in_cart` (Count / Number) — like 3
* `is_pro` (True/False / Boolean) — like `true`

> 🎁 **Superpower**: You can sprinkle any backpack item into your emails using magic tags like `{{payload.first_name}}`, or test them in **Quiz Forks (Conditions)**!

***

## How People Enter the Front Door

Whenever you shout a signal into the walkie-talkie from your app's code, you must include an identifier:

* **By Email Address**: `"email": "maya@example.com"`
* **By Contact ID**: `"contact_id": "cont_992182"`

Mailofly will automatically find that friend in your audience (or create a brand-new contact card for them if it's their very first visit) and send them through the flow!

***

## Ringing the Bell for Practice (Test Dialog)

You don't need to write code just to see if your doorbell works!

1. Click the **Test Automation** button at the top of your screen.
2. Type in your own email address.
3. Fill in funny test values for the backpack (e.g. `first_name = "Super Maya"`).
4. Click **Run Test**!
5. Watch the cards light up on your canvas and check your inbox!

***

## Up Next

* [Add a pause with The Cozy Egg Timer](delay)
* [Ask a question with The Yes/No Quiz Fork](condition)
* [Deliver a message with The Digital Mailman](send-email)


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