Cash App Pay Sandbox – iPhone Safari Approval/Return Failure

Questions
1

Hello Square Developer Support,

We are experiencing a Cash App Pay sandbox integration issue with our website, “Wanna See Something Funny?”, hosted on Replit.

Environment:

  • Square Sandbox (no live payments)
  • iPhone using Safari
  • Replit development preview
  • Cash App Pay via Square Web Payments SDK
  • Payment amount: $1.00 USD

Problem:

During physical iPhone testing, the Cash App Pay approval/account-link process does not successfully complete the expected return to our development website.

The relevant test occurred on October 27, 2026, at approximately 23:44 UTC.

Testing already completed:

  • Square Sandbox payment processing tests passed.
  • Approved Cash App sandbox test tokens were successfully processed and independently verified by the server.
  • Declined and incomplete payments remained locked.
  • Duplicate-payment protections passed.
  • Session recovery and five-minute access-expiration tests passed.
  • All 169 automated tests passed.
  • Additional sandbox-only diagnostics were installed to investigate the mobile return behavior.

We need assistance determining:

  1. Did the Cash App Pay sandbox approval/account-link request complete successfully at approximately 23:44 UTC?
  2. Did Cash App attempt navigation back to the merchant return destination?
  3. If the return was attempted, were any errors recorded during the redirect or browser handoff?
  4. Is there a known limitation involving Cash App Pay sandbox approval and Safari on iPhone when using a Replit development preview?

We want to establish whether the failure occurs during Cash App sandbox approval, the browser return, or application session recovery before making further changes.

Our production Square checkout is working correctly and remains unchanged.

Please advise what additional non-sensitive diagnostic information would help your investigation.

Thank you!

3

I do not have a cash app been close of hacked compromised

4

Please send the following in a private message rather than in this public thread:

  • Sandbox application ID
  • The redirectURL and referenceId you pass to payments.cashAppPay()
  • The Replit preview URL the page loaded from, and the URL Safari ended up on after approval (or a screenshot of the final screen)
  • Any browser console errors from the return page, plus the exact timestamp with timezone

We shouldn’t have any limitations for Cash App Pay in the sandbox. Once we have the details above we can confirm whether the failure happens during approval, the redirect, or session recovery on your side.