Modals are overlays that prevent merchants from interacting with the rest of the app until a specific action is taken.

Modals can be disruptive because they require merchants to take an action before they can continue interacting with the rest of Shopify. As such, modals should be used thoughtfully and sparingly.

The Modal action set allows you to open two types of modal: message and iframe. Message modals support only plain text content. Iframe modals allow you to fully customize the modal contents.


Create an app and import the Modal module from @shopify/app-bridge/actions. Note that we'll be referring to this sample application throughout the examples below.

Create a message modal

Create a message modal using the message option. Message modals support plain text content of any length using the message option.

Create an iframe modal

Create an iframe modal by passing the url option. If the url option is present, then the message option will be ignored.

Create an iframe modal with an absolute URL

Create an iframe modal with a relative path

A relative path iframe sets the URL relative to your app root.

If your app’s root URL was, then the example above would open a modal at

Open and close a modal

Open and close the modal by dispatching the OPEN and CLOSE actions.

You can add buttons to the modal footer. All modals support one primary button and multiple secondary buttons. To learn more about buttons, refer to Button.


You can subscribe to modal actions by calling subscribe. This returns a function that you can call to unsubscribe from the action:

All action sets in App Bridge support the same subscribe API. The modal footer buttons also return an unsubscribe function.

Unsubscribe from all

You can call unsubscribe to remove all subscriptions on the modal and its children (including buttons):

Unsubscribe from modal actions only

You can call unsubscribe with false to remove only modal subscriptions while leaving child subscriptions intact. For example, you might want to unsubscribe from the modal but keep button listeners so that the buttons can be reused in a different modal.

Update options

You can call the set method with partial modal options to update the options of an existing modal. This automatically triggers the update action on the modal and merges the given options with the existing options.

You can update buttons attached to a modal's footer. Any updates made to the modal's footer buttons automatically trigger an update action on the modal:

Set modal size

By default, modals have a fixed size of Small. You can customize the size of a modal by passing in a different Modal.Size value:

There are 3 values for Modal.Size: Small, Medium and Large.

Set modal size automatically

The setupModalAutoSizing utility allows your iframe modal to update its height to fit the page content.

In your main app, open an iframe modal:

Inside the modal page, import the setupModalAutoSizing utility to enable auto sizing:

Avoid setting height, margin or padding styles on the <body> element of your modal page, as these will interfere with automatic modal sizing. As a workaround, set these styles on a wrapper element instead.

If you are using Shopify Polaris, be aware that it applies height: 100% to the <body> element by default. You will need to override this style on your modal page.

Communicate with the parent page

It’s often useful for a modal to be able to communicate with its parent page. You can use the DATA action to send messages between an iframe modal and its parent app.

To send data from a modal, dispatch a Modal.Action.DATA action from your modal:

In your app, subscribe to Modal.Action.DATA:

To send data from the app to the modal, complete the steps in reverse: subscribe to Modal.Action.DATA in the modal and dispatch a Modal.Action.DATA action from your app.