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Use the Callbacks screen to have Fluid call your endpoint during store events, such as a cart that needs its tax calculated. For most events, the store action waits for your response, so a slow endpoint slows it down.

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Where to find it

In the admin, click the Settings gear in the top bar. In the Settings sidebar, under System, select Callbacks. You can also click the Developer Hub code icon in the top bar, then select Callbacks in the Developer Hub sidebar. If you don’t see Callbacks, your role doesn’t have access to Developer. An admin who manages roles can give your role View only or Full access to Developer on the role’s Permissions tab, in the Settings card. See Roles.

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The callbacks list

The list shows your company’s callbacks. Click Create Callback to add one.
  • The All, Active and Inactive tabs filter the list by status. All is selected when the screen opens.
  • Sort the list by Event, Status or Created At.
The list has these columns:
  • Event: the store event the callback responds to, for example update_cart_tax.
  • URL: the endpoint Fluid sends the request to. The list shortens long URLs. Hover over one to see the full address.
  • Timeout: you can ignore this column. Fluid sets the time limit for each event.
  • Installed By
  • Status: active or inactive.
  • Created At: the date and time the callback was created.
Click a row to open the callback, or use its actions menu to Edit or Delete it. If your role has View only for Developer, Create Callback is hidden and the actions menu has View instead. You can open a callback to see its settings, but the panel has no Save or Update button.
Some callbacks in this list may belong to droplets you’ve installed. Check with your team before you change or delete a callback you didn’t create.

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The callback panel

The panel opens on the right when you click Create Callback or open a callback.
  • Definition: the event that triggers the callback. Select it from the Definition menu, which lists event names such as update_cart_tax, update_cart_shipping and redirect_cart_payment. This field is required.
  • URL: the address of your endpoint, for example https://shop.example.com/fluid/callbacks. It must start with https://.
  • Timeout (seconds): new callbacks start at 5. Fluid sets the time limit for each event, and this value doesn’t change it, so you can leave it as is.
  • Active: turn this on to have the callback receive events. New callbacks start with Active on.
The panel has a Cancel button and a Save button, which reads Update when you edit an existing callback.
Fluid uses a tax callback (update_cart_tax) only when your tax settings use Custom Tax Integration or Droplet, or, in Per Country mode, when a country’s Tax Mode is Custom Tax Integration or Tax Droplet. You choose this on the Taxes screen.The Taxes screen mentions callback country filters. You can’t set them on the Callbacks screen. Your developer sets them through the Fluid API.

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Create a callback

1

Start a new callback

On the Callbacks screen, click Create Callback. The Create Callback panel opens.
2

Choose the event

In Definition, select the event you want your endpoint to handle. If you already created a callback for this event, edit it instead.
3

Enter your endpoint

In URL, enter the address of your endpoint. It must start with https://.
4

Save

Leave Active on so the callback starts receiving events, then click Save. The new callback appears in the list.

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Edit a callback

1

Open the callback

In the list, click the callback, or choose Edit from its actions menu. The Edit Callback panel opens.
2

Save your changes

Change the fields you need, for example the URL, then click Update.
To pause a callback without deleting it, open it, turn off Active and click Update. Turn Active back on when you’re ready to use it again.

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Delete a callback

1

Choose Delete

In the list, choose Delete from the callback’s actions menu.
2

Confirm

In the Delete Callback? dialog, click Delete. You can’t undo this.

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FAQ

A webhook tells your service that something happened, without holding up the store action. A callback calls your service during the event, and for most events Fluid waits for your response before it continues. If you only need to know that an event happened, use Webhooks instead. Developers can find the callback API alongside webhooks in Register and handle webhooks.
Check these things:
  • The URL must start with https://.
  • You can create only one callback for each event. If you already created a callback for this event, open it and change its URL instead.
  • The deliver_email event accepts only one active callback for your company. If another callback for it is already active, such as one a droplet installed, Fluid rejects the save while Active is on.
When Fluid rejects a save for one of these reasons, the panel closes and an error message appears, so you need to enter your details again.If an error appears under a field instead, the panel stays open. Fix the field and save again. For example, Timeout (seconds) must be a number from 1 to 30. If it shows 0, enter a number such as 5.