[BUG] [P0] Users Cannot Return to App from PayPal in Mobile Browsers Lacking App Link Support (v5 SDK)

[Keko2025]

Braintree SDK Version

v5.17.0

Environment

Sandbox

Android Version & Device

Redmi Note 11 5G - Android 13

Braintree dependencies

implementation 'com.braintreepayments.api:paypal:5.17.0'

Describe the bug

In certain mobile browsers that do not support Android App Links, users are unable to return to the application after completing or canceling a PayPal authorization. Instead, they remain stuck in the browser.

This behavior appears to be an issue specific to v5 of the SDK. In v4, the deepLinkFallbackUrlScheme effectively allowed users to return to the app. However, with v5 now enforcing the use of App Links, the SDK does not seem to adequately handle scenarios where App Links are unsupported by the user's browser.

Specifically, when the PayPal flow is initiated from a browser and uses an appLinkReturnUrl, there appears to be no preliminary check for App Link functionality. Consequently, the deepLinkFallbackUrlScheme also fails to trigger, preventing the user from being redirected back to the native application.

To reproduce

1. Initiate PayPal flow via Braintree SDK, which opens the PayPal login/authorization page in a mobile web browser.

2. Within the PayPal web interface, after logging in and reviewing details, click the "Continue to Review Order" button (or a similar confirmation/proceed button).

3. Observe that after this action, the user is not redirected back to the app. Instead, they remain on a PayPal confirmation page or a generic web page within the browser.

Expected behavior

Expected Behavior: Use deepLinkFallbackUrlScheme to return to the App if applink fails.

If App Links are unavailable or unsupported by the browser, the SDK should default to using the deepLinkFallbackUrlScheme to ensure the user is redirected back to the native app, rather than remaining in the browser.

Screenshots

No response

[small-dream]

The Xiaomi browser isn't the only one. Some Samsung and Motorola phones also don't support App Links by default, which means this issue is very serious, affecting at least tens of millions of Android phone users.

[Jake-Jiang]

Braintree's reputation is built on providing seamless, reliable, and frictionless payment experiences. A core value proposition for any leading payment gateway is to maximize conversion by removing technical barriers. Leaving a major mobile ecosystem with a broken payment flow contradicts this core promise. A truly global payment partner should strive to provide solutions, even when challenges arise from third-party environments.

[shijia2118]

so ,how to resolve this issue?

[Keko2025]

@shijia2118 For now, we can mitigate this by using an older version of the Braintree PayPal SDK, for example, something prior to v5 like com.braintreepayments.api:paypal:4.51.0, to work around the issue. We'll wait for an official update from Braintree to resolve it.

[shijia2118]

@Keko2025 okay,thank you for your reply!