# Blocks and actions

A button in a mini app has no "what to do" field. The action is set by the scheme: the button's exit is linked to a block, and a tap opens or runs that block. A block without a screen does its job and leads further through its own exit — for example, a record is added → the "Thank you" screen.

List rows, taps on an image, a card or a record, form submission and other [element exits](https://support.watbot.org/mini-apps/elements) work the same way.

![The "Add block" window with blocks by category](https://support.watbot.org/_media/en/02-mini-apps/_images/add-block.webp?v=1791781230)

## What a button can do

| You need to | Where to lead the exit |
|---|---|
| Open another screen | The ["Screen"](https://support.watbot.org/mini-apps/blocks/screens/page) block |
| Show a window, menu or dialog over the screen | ["Modal"](https://support.watbot.org/mini-apps/blocks/screens/modal), ["Menu"](https://support.watbot.org/mini-apps/blocks/screens/menu), ["Alert"](https://support.watbot.org/mini-apps/blocks/screens/alert), ["Action sheet"](https://support.watbot.org/mini-apps/blocks/screens/action-sheet) |
| Show a short message that fades by itself | ["Toast"](https://support.watbot.org/mini-apps/blocks/screens/toast) |
| Save, change, find or delete a list record | Blocks of the ["Lists"](https://support.watbot.org/mini-apps/blocks/records) category. For questionnaires, the "Record form" element is handier — it writes the record by itself |
| Send data to an external service or get it from there | ["HTTP request"](https://support.watbot.org/mini-apps/blocks/logic/http) |
| Send people down different branches | ["Condition"](https://support.watbot.org/mini-apps/blocks/logic/condition) or ["Launch source"](https://support.watbot.org/mini-apps/blocks/logic/launch-source) |
| Write to the person on behalf of the bot, start a bot scenario, tag the contact | Blocks of the ["Chatbot"](https://support.watbot.org/mini-apps/blocks/bot) category |
| Mark the person with an app tag | ["User tags"](https://support.watbot.org/mini-apps/blocks/logic/user-tags) |
| Open a link, copy text, share, close the app | ["JavaScript"](https://support.watbot.org/mini-apps/blocks/logic/script) — see [Code in the app](https://support.watbot.org/mini-apps/code) |

To book a client, cancel or reschedule an appointment, or save a visit rating, use the blocks of the ["Appointments"](https://support.watbot.org/mini-apps/blocks/booking) category.

If an exit is not connected to anything, nothing changes on a tap.

## How blocks connect

- **An exit** is a row at the bottom of a block. For a screen and a window, the exits are their buttons, rows and other tappable elements. For a block without a screen, they are the outcomes of its work: "Yes" and "No", "Success" and "Error". "It worked" exits are green, "it failed" exits are red.
- **A link** is a line from an exit to the block that opens or runs next. How to draw and delete links is on the [Builder](https://support.watbot.org/mini-apps/builder) page.
- **"Continue"** fires by itself as soon as the app reaches the block. This way you can open a screen and show a window or a toast over it in one step.
- **A chain.** Blocks without a screen run one after another until the app reaches a screen, a window or a toast — that is what it shows. If the chain ends at an exit without a link, the person stays on the current screen.
- **A "Note"** is not part of the chain: if a link still leads to a note, the chain stops there.

## Back

You do not need a separate block to go back. Screens pile up in a stack: the system "back" button and the "back" button in Telegram and MAX return to the previous screen. A link to the screen that lies right under the current one in the stack also works as a step back. An open window closes before the screen does.

## Screens and overlays

An overlay is shown over the current screen, not instead of it. An overlay cannot be the start block. A new screen closes an open overlay.

The buttons of an alert, an action sheet and a toast have a "Role": "Default", "Cancel", "Destructive". The role changes the look of the button: "Destructive" is red, "Cancel" in an action sheet stands apart at the bottom. Each button is a separate exit of the block.

## Blocks without a screen and the chatbot

Chatbot blocks have a "No contact" exit: it fires when the app was not opened from the bot or the person has not written to that bot. See the [Chatbot](https://support.watbot.org/mini-apps/blocks/bot) section for details.

Many blocks put their result into variables: the id of a new record, an order number, a refusal reason. How to show them on the next screen is on the [App data](https://support.watbot.org/mini-apps/data) page.

## Block reference

- [Screens and overlays](https://support.watbot.org/mini-apps/blocks/screens) — "Screen", "Menu", "Modal", "Alert", "Action sheet", "Toast".
- [Data and logic](https://support.watbot.org/mini-apps/blocks/logic) — "HTTP request", "Condition", "Launch source", "JavaScript", "User tags".
- [Lists](https://support.watbot.org/mini-apps/blocks/records) — "Add a record", "Edit a record", "Delete a record", "Find a record".
- [Chatbot](https://support.watbot.org/mini-apps/blocks/bot) — "Bot message", "Bot scenario", "Contact tags".
- [Appointments](https://support.watbot.org/mini-apps/blocks/booking) — "Book an appointment", "Cancel appointment", "Reschedule appointment", "Rate the visit".
- [Utility](https://support.watbot.org/mini-apps/blocks/service) — "Start", "Note".

## Limits

- One tap makes the app go through no more than 50 blocks in a row. If the chain is longer — for example, blocks are looped — it is interrupted.
- The "back" stack holds no more than 20 screens.