I am developing a Shopify checkout customisation app which includes some extensions of type 'ui_extension'. The extensions need to make some API calls, so following the documentation I have network_access = true in the extesions .toml file, but am still receiving the following error every time

20fa7b5ad880a85d8f39cf44d7b100f6.js:19537 Error fetching banner config: ExtensionUsageError: permission to use fetch() must be specified under [capabilities] with flag "network_access = true"; this can be done within your extension's configuration. View the docs for more information:

Here is the content of my toml file:

api_version = "2025-01"

[[extensions]]
name = "custom-message-block"
handle = "custom-message-block"
type = "ui_extension"

[[extensions.targeting]]
module = "./src/Checkout.tsx"
target = "purchase.checkout.block.render"

[extensions.capabilities]
api_access = true
network_access = true

I'm at a complete loss here - I've deleted the .shopify folder and completeley restarted the app in case of any caching issues but still no luck.

If anybody has any idea what my issue may be, it would be greatly appreciated!

I am developing a Shopify checkout customisation app which includes some extensions of type 'ui_extension'. The extensions need to make some API calls, so following the documentation I have network_access = true in the extesions .toml file, but am still receiving the following error every time

20fa7b5ad880a85d8f39cf44d7b100f6.js:19537 Error fetching banner config: ExtensionUsageError: permission to use fetch() must be specified under [capabilities] with flag "network_access = true"; this can be done within your extension's configuration. View the docs for more information:

Here is the content of my toml file:

api_version = "2025-01"

[[extensions]]
name = "custom-message-block"
handle = "custom-message-block"
type = "ui_extension"

[[extensions.targeting]]
module = "./src/Checkout.tsx"
target = "purchase.checkout.block.render"

[extensions.capabilities]
api_access = true
network_access = true

I'm at a complete loss here - I've deleted the .shopify folder and completeley restarted the app in case of any caching issues but still no luck.

If anybody has any idea what my issue may be, it would be greatly appreciated!

• shopify
• toml

1 Answer 1

I've found the problem this morning.

In addition to the toml entry you also need to request API access for the app via the partners.shopify dashboard.

Navigate to

apps > [YOUR APP] > API access

and under 'Allow network access in checkout UI extensions, click Allow network access' you need to select 'Request Access'

With that updated I'm able to make API calls from my extension components