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.

Version 1.0, 2.0, 3.0 of the Square payment extension is already native for all OpenCart 3.x stores. You will find it in Admin > Extensions > Extensions > Payments.

Version 1.1, 2.1, 3.1 must be downloaded and installed. Please download this version from OpenCart or from iSenseLabs.

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


How can I test this extension on my store?

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.

Note: Prior to versions 1.1, 2.1, and 3.1, the Square extension had Sandbox mode included. If you are using Square 1.0, 2.0, or 3.0, then you can use Sandbox mode for testing. Please ensure to use a testing credit card like 5555 5555 5555 4444.


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 system. Here are some tips on how to fix this:

  1. Please go to Admin > System > Settings > [Edit] > tab Mail, and carefully check your mail settings.
  2. If everything seems correct, please check your error logs in Admin > System > Maintenance/Tools > Error Logs. If you spot any mail errors, try to identify the modification causing the error, and report any issues to the corresponding developer.

In almost all cases, this issue is caused by a third-party modification of your e-mails.


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.

Important: Card payments is currently only available for merchants based in the U.S., Canada, Australia, Japan and the UK.


Square does not work with browser plugins for credit card storage like Roboform. Why?

By taking over PCI compliance, Square acts as the merchant of record. Square is thereby at risk with the merchant transactions, so they have a platform security model prefaced on having card details only be directly manipulated by the user (or his/her native browser's autofill) into Square-controlled apps/libraries/iframes. Ultimately, this helps the seller avoid many of the burdens of PCI compliance when it uses Square as its managed payments provider as compared to alternatives.

In other words, Square doesn't support browser extensions like Roboform due to security issues (specifically cross-site-scripting vulnerabilities). The only thing you can do to help your customers, in this case, is to suggest to use a native browser autofill, instead of the unsupported browser extensions. Square doesn't currently have a viable way to ensure these browser extensions cannot be compromised in some manner.