The Module does an excellent job of automatically creating Customer Invoices and corresponding Invoice payments in QuickBooks Online when they are created in WHMCS. It is able to do the same for refunds in WHMCS. It also ‘invalidates’ customer Invoices in QuickBooks Online if they are ‘cancelled’ in WHMCS.
It works well with QuickBooks Online that is using any currency, as long as the currency in the QuickBooks Online and the WHMCS are the same currency.
It has a control panel which gives you control over which Clients you ‘map’ between WHMCS and QuickBooks Online, and it has the ability to ‘push’ into QuickBooks Online past data (if you want it to), and other features.
As a technical note, you should ensure that ‘Sequential Paid Invoice Numbering’ in not ticked in your WHMCS, ‘General Settings’, ‘Invoices’, before installing this module. (If you use that feature in WHMCS, it might be best to check with the seller before you buy, as some extra work might be needed.)
The module is well supported, and paid installation and extra support is available if you want or need it.
It seems it is also possible to use the module to link more than one WHMCS installation to QuickBooks Online, (perhaps convenient if you happen to have more than one website running WHMCS), though it is likely best to ask the seller about that before ordering as their may be a slight configuration change needed when it is installed on more than one WHMCS, etc, (and I am not sure if an extra license would be needed or not).
I recently bought the module and it seems to be working well. :)