Frequently Asked Questions


Which cards does the Square extension support?

Square supports any card bearing a Visa, MasterCard, American Express, Discover, JCB, or UnionPay logo, including credit, corporate, debit (processed like credit), prepaid and rewards cards. For more information, visit the Square Help Website.


What processing fees are applied to transactions?

Square applies a 2.9% + $0.30 fee to manually keyed-in and processed using a saved card payments. For up-to-date information see the official Square Fees and Payments FAQ.


Can I enable recurring payments without using a server-side CRON job?

Yes, you will have to setup a remote CRON service. These services periodically visit a URL on your site to run a scheduled task. See Method 2 in CRON Settings for information on how to set that up.


You mention that this extension is compatible with OpenCart 3.x, but I cannot find the download anywhere.

The Square payment extension is already native for all OpenCart 3.x stores. You will find it in Admin > Extensions > Extensions > Payments.

To configure it, please watch our video tutorial, or read the section Integration Settings.


How can I test this extension on my store?

The Square extension supports Sandbox mode with your Square app Sandbox Access Token and Sandbox Secret, but you must test with non-existent credit card numbers (for example, 5555 5555 5555 4444).

For information how to enable Sandbox mode, please refer to the Integration Settings page, Step 3.

Alternatively, there is a way to test in non-sandbox mode with a real credit card. You can enable the "Authorize" method, which will not capture funds upon order creation. After placing the test order, you can void the transaction from the Square admin panel.

For developers, the Square extension also allows debug logging of every call to the Square API which is useful for detecting bugs.


When I check out on the store side I see SyntaxError: JSON Parse error: Unrecognized token '<', but on the admin side, the transaction is processed succesfully and an order is created. How do I fix this?

Usually, this error means that there is an issue with your OpenCart mail settings. Please go to Admin > System > Settings > [Edit] > tab Mail, and carefully check your mail settings.


I get this error: There are no locations capable of online card processing setup in your Square account. How do I fix it?

This issue is related to the locations you have set up in your Square account. To make use of the OpenCart payment extension, you must have at least one location in your Square account with enabled online credit card processing. For more information on how to configure this, please refer to Square's support center.